pitcher's pause
 

FP, the pitcher is required to pause on the plate taking or simulating a signal.

Is it a legal alternative in any rule set to pause, after joining the hands, before separating to actually pitch?

For example, no initial pause on the plate, just step on and join both hands and while still joined, raise them above the head, then pause before separating.

No forward motion involved here, just confirming about the pause.

Speaking ASA, no, not legal.

ASA 6-1
D. While on the pitcher’s plate, the pitcher shall take the signal or appear to take a signal with the hands separated. The ball must remain in either the glove or pitching hand.

Speaking NFHS, no, not legal.

NFHS 6-1-1
a. Prior to pitching, the pitcher must take a position with shoulders in line with first and third base with the ball in the glove or pitching hand, and with the hands separated.
b. While in this position, the pitcher shall take (or simulate taking) a signal from the catcher.

The hands must be separated.