Not sure about that charger but from the 80watts I've had over the years they never actually allowed 6A charging, they would immediately step down to 5, which is fine, but who knows yours might differ.
Also, what did you mean by a 2s cable, how are you charging it now?
On servos, for bashing I like to use the Solar D771, it's got about 190 oz/in at 6v and the EXI D226f (I think, which ever one has 180 oz/in torque) both are all metal gears and direct drop ins. Both under $20
As for that esc , 60a seams a little low but then again idk how many amps that motor can pull.
On the servos, could be the reciever, could be the servo, could be dirty connectors, could be, but not likely your transmitter. Gonna have trouble shoot that one.
3.7-3.9 is just fine for lipo storage (per cell)
The wire is a ext so i can connect the balance from the lipo to the charger easier . Pretty much makes charging easy i have a lipo bag so i charge with the lipo out of the rc some people charge well its still on there rc chassis.
I might the servo you said, but i had good luck with the power series one's value hobby sells . I might wanna step up to a higher voltage servo just cause i THINK my bec is rated for 6 volts but still i could wire up another bec to have a better flow if that makes sense to you. So i am thinking 15-25ish bucks shipped should get me the servo an the wire i was talking about is like 2.00 very cheap but a handy thing to have. I have a pack of 2s-8s balance gripers i got. Makes it a little easier to get the balance wire less prone to braking .
The 60 amp should be fine it pairs up well with the motor i did the math an i can power the motor with no issues with my 5000 mAh 30 lipo. The charger can do 6 amps but my power supply can do up to 5 amps but at this time i have only one lipo that 5000 pack so i am in no rush to go buy a higher rated power supply .
It could be the dhk gear, there electronics are not very good tbh so i might have to go get a remote/receiver combo . I would just get some entry level 2.4 setup from Value hobby.