Just a few thoughts. I've never bottle fed but I read a lot.
Baby Bargains (a famous book) has a blog in which they are currently discussing and keeping readers updated on the issue of BPA's in bottles. They are banned in Canada now and Babies R' Us and Walmart are committed to banning them soon, but haven't yet. But most plastic bottles still have them. Be aware and careful about this. Dr. Browns' still have BPA's in their plastic, though they are committed to bringing out a glass line soon. Avent has BPA's. But there's a list out there of bottles that don't -- I'd look for that list. I think its by a blog called z recommends or something similar.
Also added DHA's in formula are very controversial right now. I'd google it and see if you can find some information on it. First of all, they are from an odd source, I don't remember what, but not a naturally occurring source. Secondly, they don't appear to be usable or absorbable by the body in the form their in. Third, as a fat, they can go rancid in formula. And fourth I think there have been some negative events associated with them. Google around. The DHA's in formula are not like flaxseed oil, they are artificially manufactured and very odd.
Also remember that if you give liquid "premixed" formula, your baby may not be willing to transition to powdered. That could be fine with you, but just keep it in mind. The texture and taste are very different and the liquid formulas are much more expensive.
If you go with conventional formula, once you and your ped have decided on a good choice, there are "formula clubs" or buying clubs in which you can get it at a discount in bulk. Stick with one if possible because switching can be hard on the baby's digestion and remember to support the baby's digestion in other ways. Formula increases constipation and gassiness. A lot of sources recommend giving the baby probiotics in order to help the digestion cope with formula. There's a lot of articles online about how the administration of probiotics (acidopholis and other healthy bacteria) dramatically reduces the classic symptoms of "colic" -- google that too.
Good luck. Arm yourself with info and embrace your mothering.
I hope for you deeply that the chemo is quick and effective and you have all the support in the world to care for yourself and your baby.