About your question on Bayonetta's 0-death combo, it actually is pretty close to the cancelled double jump like you mentioned. I hadn't heard of it prior to you bringing it up, but I am able to jump a third time afterward. There are about seven hits in the first Up-b. I try to count them out then press jump and then Up-b almost immediately after hearing the 7th hit. It helps to close your eyes when you do it.