The Fet driver can be zener modded. That means it can except a 2s input. There are also fet drivers with a ldo voltage regulator, also for 2s input.
The Texas avenger driver is also an option.
The MTN buck driver can also be used with the XHP70, but since the voltage difference is smaller it can drop out of regulation. However don’t think its a real problem.
Buck drivers require an specific amount of voltage overhead, lets say 1 volt. That means to drive a 6 volt led it requires ar least a 7 volt input. If the input drops below that it falls out of regulation.
I believe that the MTN series only needs around 0.5 volts (not 100% sure), so it should be good.
The LD-3 can only work with clicky switches, that means click for on and click for off. No momentary.
“Note: some of the pictures in this preliminary datasheet are from LD-2, LD-3 is clicky switch only!”
As I understand it right your switch circuit will acts as a clicky switch. When you click it for on the circuit latches and it stays ‘on’ when you click again, it switches off. Am I right?
If so you could uses a LD-3.