Progeny from heroic rooster

[NatJ]

Speaking of more hens - the store also periodically gets 8 week old pullets. Our youngest batch outside is aged 4-5 weeks. We're thinking of getting 4 or 6 started pullets, and placing them into the small coop with the other 14 at night. Is that a decent plan?

Yes, I think that has a good chance of working.

If they really don't get along, you could separate them again for a look-no-touch introduction period, but first I would try just putting them in the same pen (when that works, it's by far the easiest way to do things!)