1. Keep that sodium formate in a safe, and guard it as a diamond, for better days to come. Formic acid can be obtained from beekeepers.
2. Don't even concider it.
3. Yes, there will be.
4. It's the needed solvent to let the reaction proceed, the boro hitting it when spooned in is directly used for the good work, but if stocked up in a dripping funnel all together with an amount of methanol, it will decompose fairly fast, and your yield will be near zero.
Btw, endless discussions on this topic can be found in TFSE.
BP formic acid: fill in Formic acid in Chemfinder search, then note the CAS number at their page only, do NOT pay attention to their crappy data, then click Physical Properties, then you get a new screenshot, click there the first top long link to InternationalPhysicalProperties Data, it's the first link on top, then fill in there -only the CAS number- (like 11-22-33 as an example only, not all those 0000 in front of them from Chemfinder), and these guys have reliable data!
I found a bp of a chem yesterday in Chemfinder which was about 200C OFF the real one in IPP! Messy data. LT/
WISDOMwillWIN