No. You gain enough Mist Charges to summon a Esper when You obtain The Esper so you don't need any quickenings. Most do not know this because they obtain all quickenings before level 2 or 3 Espers are available
No. In fact, a trick to getting an over 45 quickening chain is Getting only a lv 1 Quickening, and then getting a lv 3 esper. That way you'll have 3 quickening bars, but will have only 1 option on quickening chains.