Any A500 internal accelerator can be used 020/030/040, and these can have 32bit Fast RAM and load Kickstart into there too with a suitably supplied utility. There is no technical difference between the 1000/500 preventing such things, only the physical positioning of the 68000 socket near the side of the A1000 casing leaving less room.
As the Zorro 1 side expansion has the same lines/signals on A500/1000 then you can use any of those too, even if they are back to front, like the GVP 030 side expansion.
The only actual difference is the Agnus, as the 1mb/2mb chip ram boards are for fat Agnus then they won't fit. So 512mb chip is possibly the max for the A1000? I don't know if anyone did a 2mb or 1mb chip ram upgrade on a board type fat Agnus adaptor for the A1000.
There are WOM>ROM converters for Kickstart on A1000 too so you can have that as well.
