A lot of people. I'm not sure how many just a lot.
yes
Marissa Arena's birth name is Marissa Grace Arena.
There is no canonized saint named Marissa. The name probably derived from the name Maria or Marie. There are many, many saints with those names.
Marissa Pendergrass's birth name is Marissa Pendergrass.
Marissa McMahon's birth name is Marissa Mazzola.
Marissa Garrison's birth name is Marissa Caputo.
Lindsay Marissa's birth name is Lindsay Marissa Osborne.
Marissa Johnston's birth name is Marissa Ann Johnston.
Marissa Fiore's birth name is Marissa Lynn Fiore.
Marissa Floro's birth name is Marissa Anna Floro.
Marissa Whitley's birth name is Marissa Janine Whitley.
The name Marissa origianated in Italy