I should think it will be happy to just stretch its legs. A bit of general purpose fertilizer (not a high nitrogen one) would do nicely.
Not tricky at all. Do best in a bit of shade
paeonies are large plants with large root. A 6'' pot is nowhere near big enough. Plant them out, speak to them nicely and they should do better
fears are terrible, commonsense is over-ridden by alarmist journalism, people have become too distanced from nature and are frightened of plants, insects and goodness knows what else.
Looks like a fremontodendron
It's not a gonna. Pests don't usually kill the food crop. They'll need it next year
If it's in the hedge maybe it's been cut at the wrong time for flowering previously. That looks like a garden version, the native one has flatter flower heads