Hi! I don't know if this has been answered or not, but here goes:

If you're using the 140 Shazam or Black Adam instead of the 280 duo, can you use telekinesis to move the 140pt piece around?

Nope, it's still a double-based character.

No.

"Telekinesis
Give this character a power action and designate a target character or object (A) and a destination square (B). This character, A, and B must all be within 8 squares and line of
fire of each other. Place A in B. If A is a character, it must be a single base character [...]"

No because he's still a double base figure however Black Adam/Shazam now qualify for Fortitude because they possess instead of