Hi Jesse, I had to go and see what you’ve posted so far before I could reply blindly. So, you’ve replied to 3-4 people and I see that they have replied to you between early February and today. @TheMadFlascher was the most helpful with his suggestions on where you should start. I’m sorta a newbie. I’ve been here one year and had one grow so far with a LOT of help from some great people here.
You really need to start a journal of your own. I can’t remember how. I’ll try to see what the steps are. I started with asking a question in a brand new thread. Got some great answers and then when I finally jumped into a grow, I started another brand new threat that became my journal. That is where I post MOST of my questions, on my journal.
Another suggestion given to you and also to me when I was new, was to tag people. Read, read, read and then read more. Reply to people, give kudos on their grows, ask them about their grows, but don’t start a new convo on another person’s grow journal unless you know it’s okay with the owner of that thread.
Again, read. If you read, you’ll start recognizing the top tier folks here who can be very instrumental in helping you. They want to help but you have to ask by tagging. I hate tagging b/c I always think I’m bothering people, but I make myself tag at least half the time I post, especially if I’m asking a question. If you don’t tag, people won’t see your post unless by accident, if that makes any sense.
As for flushing, everybody is different. Some do, some don’t, some do it this way, some do it that way. I flushed for my first grow. I stopped feeding about 1-2 weeks before I chopped/harvested and then only watered. I’m wondering if you should maybe defoliate a bit. Do you have pictures? People here want pictures. We can’t tell you what to do without seeing your plants, where they are, how they are getting light, etc. You have a good description but we need pics. 
Yes! You can harvest in sections. As usual, some do, some don’t. All that jazz. But if the top of your colas are ready and the bottoms aren’t , you can harvest the top and give the lower colas/branches the light they need. Again, tho, check with your need to defoliate. Not sure what the answer to flushing when harvesting in sections, but great question.
First things first, go start your own journal. Get to know people. Read their journals. Tag them. They are here to help, but need to be tagged. If they don’t know the answers, they know who to tag for your issue. Go start a journal. You’ve got this!