I've run Lazarus on a couple of virtualised systems, but in general have preferred to have the "real thing" when possible: SPARCs and some fairly early ARMs among them. I can't remember for certain by now, but I'm pretty sure that I used Qemu for both endiannesses of MIPS when it was being brought to life, and possibly for Lazarus.
One thing I would note, and I think I raised this as a bug so that the community was aware, was that there was an installation problem on ReactOS: I think it was that decompressing files onto BTRFS generated data faster than the periodic commit operation could handle... with predictable results. Installing onto FAT with a fudged symlink (or whatever Windows calls it) was fine.
The wiki page
https://wiki.freepascal.org/Qemu_and_other_emulators hasn't had much love over the last few years, but would probably be a good place to note anything interesting.
MarkMLl