Made it three 1/1s instead of two.

5 power for 5 mana. Fairly efficient for common. I think this would be more likely to be uncommon: see Battle Screech, Spectral Procession, Timely Reinforcements etc. Captain's Call is the closest common has got to this before.

Would it be plausible for the 2/2 to be a Knight with vigilance? Soldiers are almost always 1/1s...

Compare to Knight Watch.

Plausible, but unlikely. But I will change it to Knight.

Based on other similar cards already mentioned, this should cost at least as a common.

Hmm, based on how new Knight Watch is, 4/4 for 5, I think I'd be better of going to 6...good point.

Also, it doesn't have to be Human Knights and Human Townsfolk creatures. Townsfolk are actually just Humans (there are no townsfolk cards, only human tokens) and you don't need to put the subtype in, so it could just be 'a 2/2 white Knight creature token and 3 1/1 white Human creature token onto the battlefield'.

I support the return of the Townsfolk type, and indeed a return to race-class tokens like we had in Lorwyn-Shadowmoor block.

I think 6 mana is sensible for a common that makes 5 power of tokens.

so, just Townsfolk and Knight instead of Human X and Y?

Normally tokens are just race or class, and not both. There are exceptions when the types actually matter in the block.
The number of bodies this creates makes me think it should be uncommon. It is reminiscent of Trostani's Summoner.

Class and Race both matter for this set (knight does at least,) I think I might have referenced Human once or twice, I just can't remember.

removed human type, so now it is just Knight and Townsfolk tokens.