[[boa#Finnish|boa]]

Oh no, the change made things worse. Originally there were only two affected words AFAIK: boa and Nooa, plus their compounds of course. Now the whole "risti"-category goes wrong: partitive plural becomes "risteiä". I suggest you revert the edit and figure out a better solution.

Fixed.

Thanks. The illative plural problem still remains. It is similar in nature, but the affected declension categories are not the same, see the table a little bit up this discussion chain.

Except that I just noticed an omission in the table. The words in "kevät" -category have a rare illative plural form "keväihin". I need to check if there are other cases like that.

I fixed the illative plural issue I hope, using the same method as before. I think you made a mistake with "mies" though, there's no extra -h- in the illative plural, the -h- that's there is just the noun stem.

Also "valtio" was missing from my illative plurals list and becomes "valtioiin". Otherwise it seems to work fine now.

It should be valtioihin right?

Yep.