Hi,
Baby's BOB will be much bulkier than yours because of the diaper component. Baby's needs will change as she gets older and you would have to modify as you go along.

Food/Water -
assuming baby is bottle fed
2 bottles
sterilising tablets
Plastic container to sterilise the bottles in
Milk formulae
If baby is breast fed, so much the better. You would save carrying whole lot of stuff.
For older kids, you might need to pack baby food / juices etc. Small packs of snacks

Extra clothes -seasonal
Wet wipes
Diapers
Baby Powder
Small towel
Blanket
Change mat

Pacifier
Small toy / game / book

Meds - paracetamol for kids, saline eye/ nose drops, antihistamine syrup, wind/colic drops, diaper rash cream

Lots of plastic bags for dirty clothes, diapers, puke etc.

Actually, a lot of it is EDC in the diaper bag, just multiplied many times because of the longer duration.