Can't donate right now, but I see that the goal is almost met. If I don't donate before the goal is reached, will I miss my chance? If I don't donate at all, will I be able to get it after the fact?

No you can donate until the end of the Bundle limit. 
Btw our actual goal is 20k but Itch.io wouldn't let us put it so.

Also both game will be released on itch and steam two or three month after the early access anyway, so this is a possibility too ;)