Hi Shane,
I'm not the most experienced pilot/builder either, but I may can give you some tips as where to start and what to think about.
Carbon has the advantage that it's light, stiff and pretty robust in crashes. But that doesn't mean that wood or aluminium or something like that are bad materials for multirotors. I heard that wood has really good vibration dampening properties, so that you could get away with less precise balanced props and motors. A positive side of wood is that it's easy to get and really easy to work with (wich is a huge plus when you first starting out and wanna build on your own).
I for myself went with a full aluminium frame (self made) and I'm really happy with it. It is not the lightest, but I really like it (and the fact that I built it myself).
The Tricopter frames you have there are really nice to start with, but for areal photography with a gimbal you should consider something other than a tri. A GoPro 4 with gimbal is not the cheapest thing to replace in a crash (even if the gopro lives because it's strong, the gimbal probably won't). So when you are really looking for a AP-platform, you should consider a hex or octacopter to have some redundancy with the motors and motor controllers. Even if a motor fails, you can still land with a hex or octa.
BUT: A hex or octa is just too heavy for a beginner pilot. As you will crash, you should keep your copter as light as possible (<1kg! better <800g if possible, the lighter the better) to have less inertia in a crash (less stuff breaks).
So maybe you would want to start with a quad or tri, maybe put a little keychain-cam onto it that you don't mind losing too much. A bit later when you can fly it, you can put the gopro onto your tri/quad. It shouldn't break in a normal crash, but remember: there's always the possibility that you fly into a tree/lake and can't get the copter back (nearly happened me, when I let my father fly... into a tree, lol).
A tri or quad will easily lift the gopro, but with a gimbal things get heavy really fast and a hex/octa may be the better option. But you still should start with a tri/quad and work your way up. It will be cheaper in the long run to build a tri/quad first and when you really are able to fly, then start building a hex/octa with a gimbal.
For flight control boards there are many. You should decide by the features you need and price. As a starter, I think you should go with an "acro"-type board with gyros and accelerometer, but not much else. These FCB are not expensive wich is nice, because you will crash at first and maybe one breaks. Later you can get some FCB with baro and GPS and so on, if you really need/want the features (like position-hold, return to launch). But you should start without them in my opinion, just to have less money in the air.
For acro-boards the naze32-acro version boards and KK2 boards come into my mind. I started with KK2 (have 2 of them) and when I had my windestal-type tri, I was really happy with it. It flew great out of the box, but when I cut down my arms to get a "mini" tri, I couldn't really get it to work properly. It flew, but not great, but it's possible that I really just wasn't able to PID-tune it right. Now I have a naze32-acro and it flies really great with stock PIDs.
Like I said, the reason you see next to no tricopters with a gimbal is that they have only 3 motors to provide lift, but they aren't really lighter than a quad (because the servo+tilt mechanism weighs as much as a motor+speedcontroller). So a tri can easily lift a gopro, but when you add a gimbal, it gets a bit wonky. And when you add a gimbal, you add a serious amount of money to the copter, so most pilots want to have the redundancy of a hex/octo.
Start light and cheap, work your way up. It may seem expensive to build two copters to get where you want to be, but trust me, you don't want to start with a 2kg+ octocopter with gimbal and gopro 4, crash it dramatically and throw everything into a corner and never touch it again!
The most I ever broke in a crash with my mini tri was an aluminium arm (2$) when it fell out of the air from 25m up, if that were a hex with gimbal, I would probably look at 300+$ damage at least.
Just my .04$ (as this post is too long for .02$)
-1387
