The longish round guys with many legs are millipedes.

They're cleaning up the carcass of the critter that previously used the large wings.

I think those winglike things are maple tree seeds. But they may be cleaning up my sunflowers! Should I worry about them or are they ok to have in the garden?

OKAre they a problem?
Well, do you want help from cleaner-uppers of dead stuff or not?

Millipedes dine on decaying vegetative waste while centipedes dine on other insects. The seed cases from a Maple would be a choice morsel for millipedes to munch on.