Others have answered your question but I just wanted to add something about LO not latching. IF you want to bf (I'm assuming you would from your post but if you don't, just ignore this), have you tried nipple shields? We had a terrible time of breastfeeding for the first two weeks. Bottles, formula supplements, the lot. But I tried latching her with a shield again (she'd refused them at a few days old) and she suddenly took to them. She's been exclusively breastfed ever since and about 4 weeks ago she's finally come off the shields too. Still uses one occasionally but for the most part she's fine without now.
Combi-feeding is a viable option of course but this might save you time expressing and sterilising equipment. Good luck either way!