Oh no! But then again, Oh boy, Kittens!!

Is the window well in a shaded spot? Even if it is I would try and get them out of there first. I only say this because I've seen dead mice in our window wells one day, and the next day there is nothing left but bones. Now I don't know if this is because someone poisoned them (wasn't me) and the poison ate them away like that or if the heat had something to do with it (decomposing them faster than normal). If it was the heat I would hate to see what the kittens would look like tomorrow, even though it wasn't that hot today.

Even if you don't want to bring them in the house because of Edwina, is there maybe a place in the garage you can set something up for them? Or maybe a quick run to Home Depot for some temporary fencing that you could set up a "fenced in" area for them? Not too high so the momma can jump out but the other critters can't get in. Oh what a dilemma especially since you're husband isn't home, and neither are you! Your niece sounds like she would be delighted at this new turn of events.

Good luck and let us know what happens.