FET is normally open (high resistance) but if gate pin is free floating it can be charged for example via testing with mulitmeter and FET will be in closed (low Ohm) state for quite a few seconds even without any voltage applied to gate becasue of gate capacitance.
Actually this is the way I test mosX boards with FET: I charge gate by applying x.xV for 1-2sec, and then I connect mosX board with LED to power supply to + and - pads like standard (non mosX ) MCPCBs.
At 3Amps per LED they are within rated manufacturer current which means they would be ok even on ultra cheap standard dielectric MCPCBs, so black mosled 4x is more than fine.
Ldb4 hv 6A driving 1 xhp70.2 and 1 xhp50.2 in series off a 4S battery. CNC milled housing in aluminium for good thermal properties. 3d printed gopro mount. And remote control of course. Looking forward to try it on the trails :D