White to play and draw

It's a good theme but I'm not sure about the role of the black pieces on top. I am pretty sure you forgot to sacrifice (Ra8). At any time black can play ..Rae8 and ..Re8-e1 to sacrifice an extra rook!

White will change the move order and play Kg2/g3 first, threatening Rh1#.

Neat, the moment of realisation was... neat. 

Sure. Would be nice to be able to play through parts of puzzles which are not the main line. Similarly Sd4/e5 is a more challenging attempt at defence than just shuffling the pawns forward, spectacular though that is.

Yep, there is something funny about the unused black stuff. Only seems to be there to balance material if white tries something different near the end of the solution.