Matvey
The Russian language equivalent of the name Dmitry is Dmitriy (Дмитрий).
Privet, Menya zovut - Matthew or Privet, Menya zovut - Matvey ( which is a Russian equivalent of Matthew)
Клиффорд. Pretty much a direct translation of the name.
The Russian language equivalent of the name Mark is Марк (pronounced "mark").
Douwg
Бріттні Brittni
Морин Morin
Juana = Ivana (Ивана)
Чарльз (Charl'ze) is how you would spell the name in Russian, if that's what you mean.
Jonny, Johnny
The Russian equivalent of the name Michelle is Мишель (Mishel).
The Russian equivalent of the name Jeffery is Ге́ффри (Geffri).