In the days of $5000 ICEs (has it changed?),
Yes, Ceibo has emulators that (depending on target chip) cost $600 - up.

I'm NOT going to page
Good!, paging a '51 today where you can get e.g. an ARM for about the same money is inventing square wheels.

I'm afraid the Cygnal processor is too radically different for my purposes (I use some critically timed functions) and, like you, I found the supplied 'ICE' software (I have bought one) difficult to work with. Fine for someone new to the game, and without my (too many years in the business) prejudices.
I AM using SILabs chips in "some critically timed functions" and do not have a problem. Re "radically different" SILabs got too big for their britches when they did the f3xx series, if you rely on what you know, you will get through many iterations before you get it working (RCAP2x is called something else, clock input is XTAL2 etc), but if you stick to the F0xx and f1xx series the difference is only the justified ones needed for the enhancement (e.g. SFR count). Of course, if you have the time to study and comprehend every page of a 200+ page datasheet making mental notes where SILabs thought they knew better than the normal, there is probably nothing wrong with the f3xx chips.

Erik