Specially referring to the tiles with flourishes. I realized this created situations in which people could double up on magnate bonuses for the same criteria like number of cellars. Are you supposed to remove the flourish tiles when playing with more than 2 players? Thanks!
Yes, you play with all multiplier tiles at higher player counts.
But your concern should never occur because (from page 5 of the reference book):
You are not allowed to have more than one tile of the same type.