Will Baby Yoda's Relationship To Yoda Be Revealed In This?

I suspect a definite Yes.

They'll need to attach something revelationary to this to give it some "big screen" excitement and it seems all but certain this will be it.

Once he's been tied to Yoda, he can then sacrifice himself to defeat Thrawn and co, (whilst saving The Mandalorian) in Filoni's feature, thus giving that film some big feels too and explaining his absence from the DT.