Well, in a 30 gallon it really depends on your ratio and number of angels to mollies.
Angels, in all reality and a perfect aquarium, do require about 10 gallons to themselves. Now if you happen to have multiple angels and some happen to pair off, then that one pair has a greater chance of causing a lot of havoc in that tank and will claim it for themselves.
Angels and mollies CAN go together, but i personally wouldn't do it myself. I say this because when i have kept mollies together with angels, i have always found that the mollies picked on the angels when they were young and they shredded the finnage on the angels.
As i said, its a possible matchup but with caution.
Lunchbox ... "i'm a man, but i can change, if i have to, i guess"
Tankless ... for now ... until i find what i really want (and what the wife lets me get!)