There's still a Polish speaking minority, and the language is well understood by locals. The version of Ukrainian spoken in L'viv isn't that far away from Polish as well. In practice, you can use Polish to get by, but you might need help when it comes to things such as medical care.
If you don't have Ukrainian citizenship, it's not very easy to move to Ukraine.
we need someone who can translate polish to ukrainian or ukrainian to polish.
That's not much of a problem in L'viv, there are plenty of people with a decent knowledge of Polish there.