My crowntails vant to be alone - at least, I'd rather not risk any fish with them - but the only two I've had which were sold as half moons both had wonderful temperaments.
While one was sadly lost some time back, my Silk (Mr. Never Flared in His Life) has never had a problem with the White Clouds, 'feeder' Endler-cross guppy and otos in his 15 gallon Walstad (well-planted) tank.
Based on this very limited experience, I have a tentative theory that just as crowntails tend to be crabby, super delta/half moon lines perhaps tend to be better natured than perhaps most other strains.
Of course, maybe I just lucked out with those two.
And I did, indeed, have a back-up plan...
I've never had a veiltail myself - are the temperaments generally similar?
Edit: just out of curiosity, mequro, is yours a short-fin betta?
Although I would rather not risk a long-finned betta with most tetras, I have heard some examples of people doing so with no problems.
But I've also heard endless examples of Angelfish starting out nice enough to other fish when little but turning into absolute predators as they begin to grow up, with smaller fish not only killed outright but having eyes/tails bitten off.
I hope you have an alternate plan for the Angels, away from more vulnerable fish, because this would really worry me - apparently this behaviour is normal for Angels...