280kv motors are near the limit. I would take those 190kv as they will provide more torque.
Esc wise, if you don’t mind reading up a lot then I would suggest you get a head as they are designed for skateboards.
Battery wise, just get a 5000mah 6s Lipo. This can also be 2x 3s in series.
As for charger make sure your charger can at least provide 1c charge rate to you Lipo. This means of you have a 5000mah battery your charger must provide 5amps min. . also check that your charger can do a balance charge which will drastically extend the lifespan of your Lipo.
Normally every ballanced charger will stop pushing a charge to your Lipo when it’s done.
6 months so far with lipo, no problem at all. You just have to know the limits and safety guide of lipo. Always charge them inside fire proof bag. Do not over discharge below certain voltage. Do not heat / punch / bend / puncture. Do not short’s them, be very careful while handling. Dispose swollen packs safely and immediately.
Lipo are one of the best battery at the moment with the highest capacity / density battery thought they are not the safest of all.
I never recommend more than 280KV. Normally people here go with dual 250’ish KV. It’s better to have higher kv for many many reasons. If your 300kv doesn’t pull you, then you have 2 waste expensive motors. You also want to be able to climb hill when going dual setup, if it doesnt climb / slow, theres no point of getting it. Price different are not so significant anyway.
If price is your concern, then you should go with single low KV motor. Definitely launches you on hills. I use 190KV thats a beast at climbing.
But remember 190kv is a huge motor. I’m not sure if you could fit in dual 190kv motor.
I weight 60kg and I use 190KV single motor, climb hill about 25% - 30% grade no problem.
Dual 250kv motor is my next step, wheel traction is your biggest problem at climbing hill.
I have a dual rear with SK3 280kv motors like what you have. i needed a 190mm truck hanger to accommodate them.
I have used the 150A versions of those ESC’s without any issues.
also using lipos and charging on board for over a year now with no problems.