Mighty No. 9 in MM7 style

[Terminal Devastation]

Other than making an edit, the other biggest mistake people make with MM7 style is making characters a megaman, rather than bringing out all of the characters unique traits like posture, size and to a certain extent, proportions.
Even Beck has his differences from the blue bomber.

This is MUCH easier to pull off in the long run with a scratch sprite, since you won't feel constrained to a single base, and to make it look good you'd have to severely edit the sprite anyways. Now I'll give you a few pointers to improve this that would apply to both an edit and scratchwork, so that even though I'm hoping you'd make a scratch sprite with these in mind, if you REALLY feel you must make an edit, you can improve on that.

The first issue is the posing. Now I haven't seen Beck's idle stance, but from I've seen of him, I picture him to stand up a little straighter, more like smash bros Megaman, rather than megaman's MM7 slouch. The shooting pose on the other hand is clearly more like Megaman X rather than Megaman, with the free arm holding the buster arm. His jump is also more smash bros/classic NES megaman.
Overall, Beck seems to have a bit more energetic/aggressive personality in his pose work.

The other second issue is in the details: just because megaman has it like that, doesn't mean MM7 Beck will. I'd suggest squaring his toes a bit and making the googles MUCH larger, as Becks googles are pretty much the width of his helmet. There's also differences in his lower torso (beck wears shorts), upper torso (at this scale, you're more likely to have the buttons and the vertical side stripe show than the two horizontal strips.

I'm glad you thought to remove the bracer part of the gloves to give Beck appropiately sized arms and gloves, althought I think it would be possible to show the black wrist brace and black fingers clearly in the hand area. It'd also be possible to show blue details on the foot and the black leg stripe a bit more clearly.

I hope this helps.