Yep, a collaboration is totally fine for this!
Onto feedback:
-The copyright/url is the wrong size.
-I'd have another look at the left hand notes in 5-7. I don't know if there's some sort of key-sig or clef error there, but the notes are not very accurate at all. In general I think it should be outlining a C#dim7 chord, whereas we have G#s, Ds, Fs etc.
-I feel like the rit actually starts on the third beat of bar 13 rather than at the start of bar 14.
-You're missing some harmony notes in the RH of bars 15+, that pretty much just sits below the melody in 6ths.
-The way bars 15-18 is written out is pretty confusing, and it's not very clear where the various voices actually are. The middle voice is awkwardly acting as if it is in both the top and bottom voices at the same time and at a glance it looks like there are beats missing, or too many beats in the bar etc. I would try to be really clear about what is happening to avoid this sort of confusion. Here's one possibility that condenses layers while still be readable:
but you could also do something like properly treat the middle voice as a second layer in the right hand (although the stemming might get a little inefficient space-wise).
-Why does the left hand change from octaves in bar 19? I don't really hear any particular change like that in the original.
-In bar 20, the mordent only applies to the second layer but that isn't apparent in the sheet. One solution would be to just write it out explicitly with grace notes, kind of like in bar 22. Maybe there is some other solution.
-I feel like bar 25 should look the same as bar 45, or maybe you could have an extra low D in bar 45 on beat 1 to differentiate them. At any rate, it still seems like there's a distinct hit on beat 1 in bar 25.
-Generally in bars 26-45/46-64 I think the bass needs to be bigger (and lower) to really get across this bombastic sort of style. I'd suggest making the bass into octaves, and having the LH move off of the chords when it moves outside of beat 1 (since I think a movement in the bass is more important than a restatement of a chord already played). Maybe something like this?
-I feel like the bass goes back up to a Bb in bar 33/53. It also moves down to a F on beat 3 in the same bar.
-Similarly in bar 40/60, the bass plays an F on beat 3.
I hope that helps!