Remove the domes, seedling do not need hyper humidity!
These seedlings need more/better light than the one in the picture, that is why the Mimosa plant is so stretched.
Seedlings need air exchange to develop properly and air movement to strengthen the stems.
You can leave them in those small pots for another few days, but not much longer than that.
You can also plant the Mimosa deeper, about half way up the stem should be fine.