Are beowulf and wiglaf suitable figures for an epic

Yes, both of them are. Beowulf is the superhuman hero, who is a typical figure for an epic. He kills monsters, saves the realm, finally gets to rule one, etc. But he is ultimately alone in his heroism. As for Wiglaf, he is a prototype of a courageous warrior loyal to his king. He is the only one who comes to Beowulf's aid in his fight with the dragon. Epics always have these loyal and devoted followers of the main heroes, just like they have disloyal, cowardly people who abandon their ruler in his hour of need.