To crate train my little ones I would lock them up during the day for a few hours at a time to get them used to it. I would slowly work them up longer and longer. You can also put something really yummy in the crate for them to chew, but only something you trust they won't choke on - I use cow hooves cuz mine can't chew chunks off them. I think that the 3 month old might not be able to hold her little bladder all night and could pee in the crate (most dogs don't like to pee in their crate though).
Have you considered paper training / wee wee pad training your little ones to avoid getting up a 3:45. Oh ya, as for the noise, I can't lock my little ones up at night as they will start screaming early in the morning - probably to tell my they have to go to the bathroom and don't want to mess their beds. I just let mine sleep with me with their potty box in the bedroom.
Anyways, be persistent and work up to crating overnight slowly, the 1 yr old will get over crying all night.