I will attempt to be somewhat realistic.
For example, my Elven warrior Inquisitors are in no way going to be two-handed, especially the female ones. Have you seen how skinny and spindly elven arms are ? To imagine them using a two handed sword like Iron Bull does is just weird.
As for your warrior follower, both Blackwall and Cassandra will be sword & shield since they are both the defender and protector types while the Bull, being Bull, will be a two handed badass mofo.
Well, that doesn't matter. Actually, that doesn't matter AT ALL. You said you would attempt to be somewhat realistic. Well, no offense my friend but your attempt failed. Let's get some facts straight: most 2handed swords used in combat(talking about REAL history now) didn't weigh above let's say 8.8 pounds AT MOST, that's 4 kilograms(though most swords would typically weigh around 6. pounds or so) and could be handled pretty easily ESPECIALLY if you trained with that weapon obviously. Now of course, Dragon Age is all fictional and some weapons are so exagerrated in size but still, they wouldn't be too hard to handle because even in the Dragon Age universe, they would design weapons to be properly used, to be handled easily and basically, well, to help you, not to hinder your ability to fight so I would say elves could very well handle a greatsword just as well as a qunari would. Sure, the qunari would have a bit more powerful swings, but that wouldn't matter so much because remember if it were REAL, since we're talking about possible realism here, all you would need is a good cut. So remember guys, size really isn't everything.