Remembering how the EUput pressure on Lithuania during the conflict with
China, I have a damn doubt they support their ally in the conflict with Russia. In the place of Lithuania, I wont count on anything from the EU other than requests/threats to cede to Russia.
Lithuania is in NATO, so it's unlikely to cede anything tangible. If the Baltic states hadn't joined NATO I'm sure Putin would have invaded them first and not Georgia or Ukraine.
Economically there is also not much to lose. Trade with Russia is under massive sanctions for decades to come.
the readiness of some (many) European countries to continue cooperation with the Russians as before. There are no sanctions when it comes to Russian money. I personally spoke with a large European company that told me, to paraphrase, "if Gaddafi was alive, we would sell him too. But we prefer cash and quiet deals".