I don't think a 1 coin clear is possible it doesn't start rolling win scenarios until you're into the 2nd stage of the game. so it'd be more like a chance for a 2-3 coin clear as you can at times leave the first section of the game within the first play. but the fastest clear i've seen yet is 16 and a standard clear happening with 70-200 plays. Once you hit a win scenario it actually takes you into a secondary win section which controls what ending you get. There's both defeat boss endings (baldias/that man) and win standard, win instant kill, win dragon install. (if you dont get out of the first area within a good 250 spins it will just reset the entire gamestate back to 0). Winning can happen from about 8ish different events unrelated too standard progression and each have their own dialog/things going on.
the game is structured as stages 1-4 called drives. blast drive and heaven or hell.
stage 1 has a cutscene or can proceed into 2 from 2-4 a win scenario can happen from 8 events untied to stage but if proceeded to stage 4 it is a heavan or hell encounter to win. hoh is the fighting game part of the game, winning these can take you to win scenario and can happen at any stage. after winning this takes you into blast drive. you have to roll good enough on blast drive to get to a boss but usually you do as long as you follow its scripted directions. but it will have you roll a guilty bonus and this determines what cutscenes you see. so it really depends on what you would define as fastest clear. even once you hit a win its usually about 40ish free plays and after that you could win or be defeated.