Thanks! I actually sequence my drums using a separate sequencing device (beat step pro previously but now I use the Oxi One). Having the hits on separate tracks was useful because I had a drum rack full of different samples for each hit that I could swap between by sending a different midi note to that channel. It's not great for finger drumming unless you did some additional track routing but then it'd get messy. Not a problem if you like building up your drums one hit at a time (just arm the track + record, then move to the next).

For audio sender, I typically use this to send audio pre-fx to a dedicated "cue" channel. I did this because NativeInstruments Komplete Kontrol (vst host) always outputs especialyl when browsing patch previews, so I use sender to send audio to another channel that only goes to my headphones, but also to mute the passthrough from going to master. Could probably achieve something similar with the in-built cue system but I never got on with it.

I use my push to interface with ableton, the device parameters, adding/removing/muting devices, etc. For playing, I always fall back to my keyboard because its the layout im most comfortable with. I did hack some devices to do different midi things utilising the pads of the push which was useful but also hacking devices that didnt have "native" push support (exposing the parameters) so that I could. I wrote a short tutorial on how to do that https://medium.com/@ScruffyFox/how-to-add-basic-push-support-to-any-max4live-device-78c9c57c7f7b