The vine in the first picture looks alot like a cypress vine. If it is beware, it reseeds profusely! I planted cypress vine once about 7 years ago and it still comes back every year! And the plant in the second picture is a type of cuphea.

Do the caterpillars look like this?

If so, they're Gulf Fritillary butterflies. Similar looking black & white ones are Zebra Longwings - our state butterfly. Both feed on passion vines.

Hi Carol, yes, those are exactly the caterpillars! I thought it was something good so I've been letting them munch away. Thanks for confirming.

My first guess it that the flowering plant is a Cuphea hybrid
‘Starfire Pink.’

Have you seen a flower on the passion vine yet? It looks like a good one if the caterpillars are munching on it and doing well. Generally, passion vines with red flowers tend to be poisonous to caterpillars.

tom123, there is a flower almost ready to bloom, so we'll see. Yes, caterpillars are busily eating away :) Thanks for the ID on the flowering plant, it's a pretty little thing.