Could a Gumdramon X5 be possible by adding Gumdramon Footmon Blastmon Ekkakimon and Soundbirdmon?

Answer 1

An hypothetical Digixros between all these Digimon is possible. The thing about Digixros is that, unlike DNA Evolutions, every Digimon can be mixed with seemingly no restrictions since levels don't exist in Xros-related media.

However, it is impossible to say if the result would be named Gumdramon X5. It is actually really unlikely since up to this point the only Digimon to ever receive this name pattern are Shoutmon's main line of Digixros that was made for the show. To add insult to the injury the writers eventually lost all interest in giving proper names to new Digixros forms, by the time the Hunters arc started they just decided to name any new forms just Xros Up + Digimon name, regardless of the combination or situation and the only ones who didn't get this treatment were combinations that were already named in first place.