Oil line from the oil pump goes into the intake manifold, not carb. Oil mixes with fuel downstream from carb.
With Malossi kit, I think still works the same way. If you want to disable oil pump, I think all you have to do is remove the shaft that engages with the crankshaft, it just slips off, then drain your oil tank, and reinstall the oil pump without the shaft.
You can premix gas by adding the appropriate quantity of oil to gas tank when you buy gas at the station. Or, premix it at home in gas can.
Decide how much oil to run? Oil pump is delivers approx 2.5oz per gallon, I run 3.5oz because I don't know any better. Seems like BBK needs more oil than 49cc OEM engine. I don't have the Malossi PHBG carb (still running the OEM Keihin carb) but I add 1oz premix oil when I add 1 gallon of gas at the gas pump. My oil pump is still connected, so with another 1oz of oil added to the fuel tank, I am running approx 3.5oz oil per gallon of gas.