Remove a screw stripped head with the reverse and hammer function of a power drill, instead of a lefthanded drill bit?
can I use the normal (right-handed) drill bits, and the Reverse
function of the power drill to undo a screw with stripped head?

NO it will not grab onto the head.
The reason the reverse bit may work is because the cutting part of the bit is designed to cut into the surface, when it starts to  cut or grab it then turns the screw counter clockwise.
A normal bit will just spin and not &quot;grab&quot;.

My DeWalt power drill/hammer/driver has the Hammer function, so
combining with the Reverse function, it would additionally help?

No the hammer function will not help.
A screw extractor set is far better then a reverse drill bit.
How to use a screw extractor.