Heitor = HEY-tor (short "o") Márcio = MAHR-see-oh (the a is long, the rest is short and snappy) Salomão = sah-lo-MOW/soh-lo-MOW (the "ão" at the end is kind of like a nasally grunty noise... I'll search for a pronunciation guide online and edit it in later)
I'm not sure about Viriato, but if I had to guess I'd say vee-ree-AH-toe.
This is the Brazilian prn, btw. But Brazilian names and Portgual Portuguese names are very similar, if not the same.