Heya jokerlola,
My research (limited) has turned up, some do some do not. All agree tho it does stress the plant when you do cut the popcorn flowers, and of course trim the canopy.
Personally, I trim those popcorn flowers and the lower leaves only twice in flowering, and the last trim I always make sure is at least three to four weeks before harvest. You can tell my girls are stress from this trimming for a couple days or so, but they come right back full force. Just keep in mind on the leaves, your girls will not grow new leaves once flowering has set in fully (like yours are now).
Now, on the flip side, and deciding to keep them. I've done this myself a couple times just to see how it effects yield. So come harvest, I have a ton more trim that I use for making oil and butter (WOOT).
Hope this helps =)