I wouldn't take a new foal or mare if you are doing it for Elle's sake.
Only take the animals if you have the time, space, money, and desire to care for them properly.
If your friends are desperate and you have the space and money, maybe you could take the mare and foal long enough to resell them for your friends.
Don't do it for Elle. She would probably be much happier with more time with you, rather than having you be distracted by new additions to the horsie family.
Don't blame yourself for the lost foal. These things happen, and your presence wouldn't have made any difference. Sorry you are going through such a rough patch.