I just took autosaves off EoDII and it did still crash on scripted version - its not 100% conclusive that non-scripted version won't go with autosave on but I've not seen it do it yet and have been doing a lot of year jump / -ai testing to try and narrow down source of problem.

Maybe being a BI provinical modfodlered mod causes a problem?
wouldn't explain any difference between FATW and EoDII. I did recently find apparent problem with a newly named faction in M2TW mod-folder not wanting to look up main folder textures properly (and erratically) - if you have new culture in that would be only equivalent I could think of that might cause problems, as I think we're both on vanilla faction names.

Could even be machine related, I could try running FATW -ai with autosave enabled and see if it behaves on mine, saves do get bigger as game advances, so there could be something about a progressively increasing load, have you tried watching CPU/memory usage while its running? I was also wondering if complexity of script might be causing me problem rather than specific bug - as having half script contents in EoDII seems fine regardless of which half it is... (symptom to my crash with script is pretty similar to the "30 mins in, occasionally" on -ai )

If it is the amount of stuff getting checked that's problem and you're not scripted you could try running without trait and anc triggers, you're probably got more on that than I have.

I haven't done changes for enums or lookups.

no idea why saves would be different between normal/auto, its easier to speculate on why it might go wrong on -ai etc as I suppose it could be trying to do the operations too fast.