Is the big cage safe enough for babies?
I don't see any problems as long as they have enough room in the big cage. The older boys should take on the roll of caregivers for the new kits.
Then you just never know.

When adding new chins I always recommend having the second cage, as it may not work out.
You may have to have the two kits in one cage and the older boys in another, indefinitely. Unless your prepared for that don't add new chins.
Even buying the one may not work out , so at least with buying the 2 kits all will have a cage buddy.
