Mulch do help keep them down or make sure to remove any fruit that rots or drops off so that the seeds in them do not sprout. The fruit is ripe when either it falls off or will come off by just tugging it a little. You can eat the pulp and there is various recipes that use passiflora.(search the web) You do not need to cook the fruit. Below is a link to a website with 2 pages on edible fruit of passifloras. Hope this helps!
Mike

Here is a link that might be useful: Passiflora fruit