Could you describe the sanctuary nearby? We live on a typical city lot, and I am going to try to become a mini-sanctuary over the next few years and would love working examples.
Be careful of your city bylaws. I grew a wildflower garden in my backyard in Canada and got a complaint once. Given that the neighbour to one side asked be to do it makes me think it might have been the neighbour on the other side :-) I actually didn't mind cutting it down because I was moving that year anyway, but it pays to talk with your neighbours and find out what the city requires. It is especially important to understand what is and is not a noxious weed and to be on top of keeping them out of your sanctuary.
Ah in that case I don't think you'll have a problem. I had white clover, camomile and timothy hay (the latter I don't recommend, but it's an annual, so easy to recover from ;-) ) in the front and didn't get any complaints about it.
The back yard was HUGE. I had wild daisies, black eyed susans, and a variety of other wild flowers. The previous year I'd grown it in order to bring in butterflies, etc and my one neighbour really liked it because they could see it from their second floor windows. The way I did it was to grow it into about the middle of July and after most of the flowering was finished to mow it down.
I think the other neighbour was trying to sell their house that year and instead of just telling me they made a complaint to the city. In fact, I'm willing to bet that it wasn't my neighbours (who I was friendly with) but their real estate agent. Like I said, I was not worried about it at all, but having the city inspector to come to your house and demand that you cut your garden is somewhat stressful (especially if you were planning to grow it out).
You may get some push back from neighbours about the white clover because it is fairly invasive, but probably there isn't anything they can do about it. Anyway, good luck with your lawn! I really enjoyed mine. If you feel like it, mix in some camomile when you overseed. I think you won't regret it (low growing, super soft, smells nice and pretty yellow flowers if you let it grow long enough).
On my lawn I have clover, daisies, dandelions, and fescue. Fescue is the only one I planted.
The bees are quite pleased
We have a lot of rain in Waitati and I do not water it. Three years ago it dried out and large parts went brown. Came back happily when the rains came back
The GP's neighbor sounds like they have their panties in a bunch but going out of your way not to offend/annoy those kind of people is just the reality in those kind of places. If you want to live somewhere "nice" but not the middle of nowhere you need to conform. Unfortunately things like having a large garden, having parties, having a project boat, or collecting late 80s vintage cars do not fit within the scope of "conforming" for the purposes of the upper middle class suburban neighborhoods that most HNers will settle down in. The GP didn't conform so his neighbor complained and someone sent him a letter on official letterhead. It doesn't really matter who's letterhead it's on.
Only well off suburban/urban communities the resources to justify mediating disputes to the tune of "my neighbor's hobbies look/sound/smell offensive". If you want freedom to do what you want on your own property you need your neighbors to either have bigger problems or be far enough away to not care. Those places don't generally have good schools or aren't within commuting distance of lots of good jobs. There's tradeoffs to every approach.
This is something I have never really understood. If your neighbors can hear or smell your hobby, then you are not really staying contained on your own property and neighbors who complain are not trampling your liberties, just asserting their own.
Not whining over the slightest inconvenience is part of existing in civil society. Complaining about your neighbor using an air hammer on steel at 11pm, ok. Complaining about your neighbor using an air hammer on steel at normal hours = not ok.
It all comes down to being reasonable and in middle upper class suburbia the Overton window of what is reasonable has moved to favor the complainers over the people who want to go about their lives to the point where those places have seen fit to legislate (or enforce via HOA) what is "reasonable" and that inevitably turns into a race to the bottom.
Hearing or smelling something from a neighbouring property is just something you have to live with. Just like leaves that fall off a neighbour's trees into your property, may be a pain to tidy up, but that's just life. Sound and smell travel, should I have pave over my garden because you have allergies or don't like the smell of my roses or the manure that I feed them?
Not the parent, but my situation is similar to yours and so I'll offer my experience :
First, raked out [thinned / dethatched bermudagrass rhizomes] an area roughly 100 square feet. Broadcast region-appropriate wildflower and herb seed mixes [I'm in the southwest, but regional mixes are available everywhere].
Planted lots and lots of herbs in containers - mints, basils, and every kind of kitchen herb. Herbs tend to attract masses of bees with their yummy inflorescences. Had the added benefit of creating a supply of fresh kitchen herbs. I started out with probably two dozen herbs in containers the first year.
Planted lots of sunflowers in borders and pre-existing beds. Bulletproof plants that attract an alarming number of bees. Also had the side benefit of attracting a flock of feral lovebirds [!], who ate not only the seeds but the flesh of the plant [!!]
Planted a goodly number of squash and pumpkins all around, wherever space permitted
^ that was the first year, and boy I tell you, did the bees ever come! I was amazed to see mobs of bees on the sunflowers and gangs of bees fighting to occupy the pumpkin blossoms. They teemed on the spikes of mint flowers and buzzed in the chicory. All this with very little effort -- the above plants require very little maintenance beyond judicious watering. The one 'trick' is to water with a fine spray wand while the seeds are getting established, so as not to dislodge them.
The second year, I planted sweet clover [Melliotus altissumus] and flowering fruit trees [peach, citrus, apple] and spread more wildflower seeds around. The sweet clover grows tall but pays off with just ridiculous amounts of bee action and great aroma.
The original wildflower planting had already 'established' and a lot of the annuals in there self-seeded. Same goes for herbs like basil. I planted even more herbs in pots the second year, going for more variety, and carrots which if allowed to flower are massive pollinator attractors.
The bees came in droves -- all kinds of bees, not only honey bees -- I mean big black carpenter bees, little shiny orchard mason bees, black-and-white-striped bees, bees that live in the ground, all kinds. Plus a great many other insect and bird pollinators. Plus more dragonflies!
And it just kept building like that, with the plants doing most of the work themselves. Now the place is like 'The Secret Garden" or something, always abuzz with bees and I'm quite sure that it's the nexus of bee activity in the neighborhood. In fact, it worked a little too well, with one colony of bees establishing itself inside my laundry room wall, haha! [but that was an anomaly]
We don't have an HOA, but an annoying neighbor did complain about the wildflowers one year, citing a dumb city ordnance prohibiting grass over six inches in height. The city came to inspect and basically said "uh yeah, we're not gonna issue a citation against a wildflower garden."
Lot size in my case is a quarter-acre, but I think based on observed results that a real impact can be made with almost any lot size. For reference, I broadcast about two pounds of seeds in total the first year, and usually "re-up" with a pound or so annually, depending on how things are looking. Overall, one of the most satisfying endeavors I've undertaken.