Does a Wizard gain treasures from a charmed monster AND flee a second monster during the same combat?
No. From the FAQ:

...if you use an ability to make one monster disappear, you cannot claim
levels and/or Treasures for beating it (depending on the method used)
unless you can then kill or defeat all the remaining monsters. You
cannot, for instance, use your Wizard to charm one monster and take
its Treasures before fighting the rest. Combat isn't over until the
WHOLE combat is over.