For the PBE changes on fiora, does 1 Lounge(Q) to tower does more damage compare to 1 auto attack?

Q doesn't replace an auto-attack; it's used while the swing timer resets.

Fiora has mana issues, so I'm just wandering if it is even efficient to even use q on towers.

Weaving Qs in there is going to be more damage than just autoing, which means she takes plates faster and splitpushes harder.

The damage dealt is based on Q rank and on hit effects the fiora has like . So yes the Q can do more damage than a auto attack IF she has an on hit affect item and maxes Q.