D.K.
Congratulations! The baby could go with you for the beginning & older child can be told, the baby has to eat at night. Then when older the baby's crib can go in the toddler's room. The baby boom happened in 2 bedroom bungalows, this is totally do-able! Don't worry, just deal with things as they come, you won't change anything by worrying.
Good luck!
D.