I picked up a Acropora millepora frag about a month ago. I currently have it located very near the bottom of my display. It is still brown and hasn't colored up. Where do you have your milleporas located in your tank?
FWIW I have a pink milli frag that went green, when I asked about it I was told that was normal and when it starts growing and gets a few branches it will go back to pink. Perhaps yours will do the same thing?
I have some millies on high light high flow..They love it, you will see them getting very fuzzy..IMO..the stronger the flow, the fuzzier they get..(disclaimer--not "blowing off the tissue" kind of flow..lol)
All my milles are the highest up. To me, they color up the best. You need to acclimate corals if you have similiar lighting to the previous owner. Otherwise, it is just common sense. If I bought it from a 400 watt 10k tank, then keep it high. If I bought from a 250 watt 20k, then I would need to start below half and move up.
If they aren't mounted I grab em anyway I can get it safely. When I move my birdsnest colony, I just grab the branches lightly like a ball and move it. I've never had issues. when I glue I gently press down on the tip or use the sides if I can.
I have mine in the middle of my tank under 2 175's mh. It has gone from reddish to pink. I also have a green one that was dark green now light green with orange tips place high in tank. Green gets high and red gets low flow. Middle to upper is good placement.