Bottle rejection advice?

Definitely look at changing the stage on your teat. That worked for my son - he refused the bottle he used to have and accepted it when I changed the teat.

Regarding night waking - they often start doing this around the 4mth mark because their sleep changes as well... .they start waking up completely from their sleep cycles so you need to teach him (if you haven't already) to self-settle. A last night feed from you should be adequate - he doesn't actually need to get it from a bottle to sleep through, but I hear that you want to get some rest.