They are pretty hardy. Maybe med flow is better. They can adjust to higher light but i found mine prefer low to med light on the sand bed. My large one was smaller than yours in when i got it.
You can target small amount of oyster feast or put a few drops in the flow it makes the lps open up they sense food around , then you can target feed when they open.
When i feed my lps. I turn off my pumps. Just place a mixture of coral food in the water. The food gets around the entire tank and the corals sense it and pop out the feeders. As for the favia they can have feeders for days after the feeding. There is still stuff in water they will pull out. I have had some send out feeders after a few hours of introducing them into my tank but some rarely see feeders. Just keep good water quality and it should be fine.