porting a game the size of aus to game maker studio 1 would be pretty annoying, mostly because of the playtesting effort involved. a lot of things will break due to the changes between gm7 and gms1 so you have to make sure EVERYTHING in the game still works as originally intended and if not, you have to figure out whats going wrong and fix it and retest it. maybe it wouldnt be that bad depending on how many things go wrong. ive ported a bunch of my old gm8 games to gms1 but they were all pretty small and simple.... one of the problems i remember is that anything which uses "instance creation code" needs to be modified because they changed the execution order of that, but i dont remember anything else specific
i have pretty much no experience with making android games in gms1 but likely that will cause even more problems and you have to go through the whole playtesting and fixing cycle again. the html5 module is all kinds of broken compared to the windows one so i dont have high hopes for the android one. you also have to make mobile controls and stuff but i expect that will be a minor issue compared to bugfixing. its basically how much effort are you willing to put into replaying aus over and over and fixing all the weird bugs you find
if you port to gms2 than even more shit will break because they changed a lot between gms1 and 2, so i recommend just using 1 if you can