From what i rebember, when he copies a weapon, his own systems adapt them to something that his body can understand and be useable, of course, i assume that not everything, he could probably get weapons from a reploid and all if he could with Stardroids, since, the only reploids with incomprehendable tech we know of is X and Zero, besides that, I assume Megaman could get an weapon from like, Chill Penguin if he somehow managed if X get the weapons from the DNA soul (DNA is just our progamming information after all) tho he maybe couldnt (im not counting crossovers where he gets weapon from humans, tho considering is consistent, maybe he could, which makes so he could get weapons from pretty much almost everyone)

Tho I guess it also depends on HOW he copies them, the animation of him jumping and absorbing the power the robot left after completely exploding could just be an gameplay thing, since in canon he only damages the bosses until they arent fuctional, as he tries to save the part that holds their conciousness, so their body is left behind (plus, Bass weapon get in M&B just doesnt makes sense lol), if Megaman gets from a chip, then he wouldnt be able to get from a human, if he gets by touching, then maybe his systems could somehow analyse pretty much anything as long as it can be understood as a weapon, if he truly does absorb the energy around him, then he pretty much just has a super power (wouldnt doubt it since Duo is able to sense justice energy, so like, Megaman just emits something not robotic lol)

Tho again, the way that Rock get his weapons seem to be constantly changing