[ggx2]

My 2c:

I speak Latvian, russian and a bit of Polish. I could easily imagine a Slavic interlanguage, as knowing russian helped a lot with Polish. Learning russian took a lot of effort, though.

So, besides having a bunch of shared nouns, adding Baltic languages to the mix does not make much sense IMO. Despite having a shared ancestor (in theory), Baltic languages are not very mutually intelligible with Slavic.

Edit:

And also, if it does take on this impossible mission, it should at least be called Balto-Slovio.