I'd suggest being wary of PVA depending on the size - the reason I say this is that it requires exposure to air to set, so whilst it may appear to have dried round the edges of a large piece, the centre will effectively be protected from atmosphere and so stay as fresh as it does in the bottle.
2pack epoxy, with a test that it doesn't dissolve the foam ( slight possibility so just check)
Hey. I work with foam on a regular basis. Here is my suggestion for gluing two foam pieces together. Buy spray foam. Spray on both pieces and press together to collapse the spray foam and separate. Wait a couple minutes for spray foam to get tacky. You can touch spray foam with finger and if sticks to your finger and comes off in strings, it is tacky enough. Carefully place two pieces together. At this point they might not come apart too easy. The nice thing about this is it doesn't eat the the foam away and is super strong. I've installed cornices on high rise buildings using just spray foam and stood on the cornice afterwards
I use gorilla glue for this, makes a super strong bond, but does have a very slow drying time and expands and will ooze out of any cracks if you overdo it, you only need a sparing amount spread thinly with water.