Mosfet between Li-ion cell & charger

I'm building Arduino based project that charges/discharges 18650 cells I've gathered and I've missed a one large point while designing the system, my mosfet selection...

Being a mosfet virgin, not only did I not get logic-level mosfets (they still open enough to do the job) but I also got N-channel ones (IRF3205) where should have gotten P-channel. Nevertheless, they are soldered in now and I'd rather not have to change them out but instead re-purpose them.

Since I want to switch between charge & discharge mode, I originally had the mosfets on the positive 19v inputs for the buck converters (which then powers the chargers @ 6v) but that's what a P-channel mosfet is for, isn't it

So I moved them to the negative input of the buck converters instead. However, all grounds have to be common so the buck converters power on regardless since they still get grounded by the charger.

My question is, if I now move the mosfets between chargers and the cells on the negative line, would they're presence affect the chargers ability to detect the correct voltage and charge them safely/correctly?

Thanks