That does appear to be the plan, keep the Disney (+) brand entirely family friendly (up to the PG-13 of Star Wars and Marvel) and let Hulu house all of the more mature stuff or stuff not traditionally associated with the Disney brand (such as the back catalogs of Fox's brands, Touchstone, Miramax, Buena Vista).
It also sounds from PR that despite taking control of Hulu, Disney also has interest in Hulu remaining their Live TV offering for non-Disney channels, and that Disney would still like Hulu to be a welcome home for what Time Warner and NBC Universal content it can continue to license, though that will probably start to get weird in coming years. It probably would still be in Disney's interests that Hulu seem a "neutral" or "cable" brand, especially given the actual cable infrastructure that AT&T (Time Warner) and Comcast (NBC Universal) directly control.
Im not saying it is or isnt the plan, but weve only really seen it as the plan from the press speculating. Disney hasnt really come out and said what IT wants to do with hulu. A year ago, Iger said they were going to continue to fuel it with content. Everything else is conjecture.
That's fair, it's all mostly going to be conjecture until we see actions in the Fall. I tried to couch my wording as what I've read and how it sounds in between the lines of shareholder reports and generic statements that could be taken either way until we see action.
If money is speech, Disney has been talking a lot in how much money it has spent on both the Disney+ project and the Hulu buyout. But speech of the money will always be a bit of reading the tea leaves and the color of the wind.
Indications to shareholders are that Disney expects to make Hulu an international brand.
Also, Disney seems to have renewed Hulu's exclusive contracts for Cloak & Dagger and The Runaways, so it sounds like Disney is very prepared to take a "split" approach to Marvel with Hulu being home to an interesting subset of Marvel properties. It does sound like R-rated films like Deadpool will be on Hulu rather than Disney+, at least based on conjecture so far.
(I also wouldn't be surprised if all of the Fox X-Men stuff ended up at Hulu rather than Disney+, rather than confuse young fans of the current MCU. It may be Disney makes the dividing line be the "Marvel Studios" brand, of which the Fox films were not. But of course that remains to be seen.)
This is why Disney started the Touchstone Pictures label in the 1980s, so it would hardly be unprecedented for the company to maintain separate streaming brands for family and mature content.
It also sounds from PR that despite taking control of Hulu, Disney also has interest in Hulu remaining their Live TV offering for non-Disney channels, and that Disney would still like Hulu to be a welcome home for what Time Warner and NBC Universal content it can continue to license, though that will probably start to get weird in coming years. It probably would still be in Disney's interests that Hulu seem a "neutral" or "cable" brand, especially given the actual cable infrastructure that AT&T (Time Warner) and Comcast (NBC Universal) directly control.