[aseipp]

You can in theory clock the Agilex/S10 parts up-to 1GHz, but something like 600-700MHz sounds more realistic, yes. (Note that this is in the same ballpark as what Virtex UltraScale+ can do too.)

Also, regarding point 1 -- and I'm sure you know this already, but this is for everyone else -- you have to be careful when talking about "Logic Elements" with most of the industry because, even when describing 6-LUT parts, Intel/Xilinx often list "Logic Element Count" to mean "Number of logic elements when considered on a normalized 4-LUT basis." Both Intel and Xilinx do this and I guess it kind of makes sense; only their highest end parts are non-4LUTs so they're the odd ones out when compared to everything else in the industry. So when you read "Number of LEs", they normalize it to 4-LUTs since that's what your competitors (or older parts) would use, when accounting for density.

For example I have a Stratix 10 card in my server that has "Millions of logic elements" when you look at the product tables, but that is taken on a normalized 4-LUT basis. There are actually "only" about 900,000 ALMs on the device, with each ALM being 8-input and fracturable. So TL;DR the numbers between the low-end Agilex-D part and the Cyclone part is maybe not that far off.

[FullyFunctional]

100%. For the record, the metrics I care about, and the first I seek out, is blockram cycle time and total device memory capacity. Unfortunately, unlike say Xilix/AMD, Intel doesn't publish that number directly, but Xilix/AMD's fastest for is > 800 MHz for the lovely Artix US+ and it has loads of memory.

The LUT count is a murky beast beast as you realistically cannot use them all lest P&R times shall be counted in weeks.