Mine often take a break or two during season
Congrats!!!
Personally I'd hatch them at the same time and give her the babies as soon as they have their feet under them OR bring all the babies in to brood and give them back to her when the temps are high enough to not worry about them.
Mine all started the beginning of February. Just now starting to get into the mood to go set. I'm much further south than you and we've had a very mild winter this year.
I'm not using the incubator this year as there is just too much going on around here.
I candle goose eggs often... and mine normally take 30 days in the homemade incubator I have. Upon candling you will see the gosling in the air cell area once it has internally piped.. lock down doesn't have to happen until then.