You can even tap the Songcrafter itself to Harmonize the spell, so there will be a minimum discount of 3 lined up cunning removal from your opponents notwithstanding
Red can easily generate mana advantage as well, be it through bursty rituals (Irencrag Feat), treasure tokens (Dockside Extortionist), free spell/polymorph effects (Fires of Invention, Tibalts Trickery), or the occasional outright mana dork/discounter/mana multiplier (Leyline Tyrant, Mana Echoes)
How many had a beer accidentally spilled on them or were drawn on by an unsuspecting kid
You then get Lefou back to your hand and can exert Madam Mim to play Lefou again, ready her again, challenge again, etc
When any Dragon you control attacks, you get to draw a card for each attacking Dragon and then put a permanent card from your hand into play