you have 1 person who offered to watch the dog for you and is following through, and you have another person who had plenty of time to offer to help and is being flaky. I'd go with option 1. Trying to work something out for sake of EW's happiness isn't your responsibility, and your EW doesn't extend that courtesy to you. So I don't think it is petty.
H 34 W 29 BD 3/12/18 Divorce Busted Spring 19
It is not things that bother us, but the stories we tell ourselves about things.