Hm.... Well, if Charak could perhaps provide some kind of reasonable in-character backstory that explains why the two would match together (and that means they have to have a kind of conjoined origin story, not that they met somewhere and eventually grew to be best friends or anything like that) in the context of this RP, then maybe it could work?

As for Elecmon...I don't think I personally mind him having these three specific Mega forms. If I'm not mistaken, it seems like he's using BanchouLeomon as a kind of...Ultimate Mega, which many Digimon, including Agumon's ShineGreymon to ShineGreymon Burst Mode, actually have? I may be mistaken about that. And the DNA Digivolution between the two could be reasonable if he could provide that origin story I mentioned above.

I think that it could potentially provide for a rather unique and interesting character if he can find a way to make it work within reason.

Here's a possible suggestion for the two perhaps (and tell me if you disagree)? The two Digimon were originally one...but for some reason (perhaps something that ties into the plot, or perhaps it's something different altogether), he was forced to divide into two DigiEggs. One could hatch into Commandramon, who represented his fearsome, ruthless side while the other egg hatched into Elecmon, who could be his more peaceful, caring and/or compassionate side. The catch? Neither of them know what they originally were. Only that the two were bonded together in some way.

Do you think that might be sufficient? Personally, I don't have a problem if he has something like this to explain the relationship, but I am but one person. So it's still up to the rest of you.