Hi there "plisken". Please read the
forum rules for posting (click here). You seem to be missing a couple of things!
this room is roughly 17' by 10.5' with a 11' ceiling.
It's a decent sized room for a control room, a bit on the small side, but still usable. Not ideal for mastering, though. Mastering suites usually work better in larger rooms. However, you do have good ceiling height. That's excellent.
A friend suggested that I could fill it up with insolation and just cover it all up with a fabric? Or should I go dry wall? maybe a 3rd option I'm unaware of?
Unfortunately, it's quite a bit more complex than that!

Control rooms are "critical listening rooms", and mastering rooms even more so. There are very specific requirements that the room must meet, acoustically, in order to be usable as a mastering room. For mastering, the room must be acoustically neutral: it cannot "color" the sound. It must not add anything to the sound coming from the speakers, and it must not take anything away from that sound either. It has to tell the truth, sonically. In other words, what the engineer hears when he is sitting at the mix position, must be just the speakers, only the speakers, and nothing else. No reflections from the walls, floor, ceiling, console, or desk, no modal resonances, no early-early sound, no SBIR, comb filtering, or other phase cancellation issues, smooth reverberation and decay, flat frequency response, and a bunch of other things. If you take a look at ITU BS.1116-2, you'll find the set of conditions that a control needs to meet to be usable for mixing and mastering.
Take a look at this thread: scroll down a bit to see the results of the room tuning process for that studios. That's what the acoustic response should be for a room that is intended for serious mixing and mastering.
http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471
Second thing is optimal placement for my desk and monitors,
That's actually first, not second!

Correct placement and geometry for the speakers and mix position is the very first thing that needs to be done for the room. The speakers and mix position must be kept out of the room nulls, and located such that the artifacts caused by phase cancellations from the walls, floor and ceiling do not fall at important points on the spectrum, and can be dealt with using suitable treatment at the correct locations in the room. There are "rules of thumb" for getting all that that right, and methods for measuring the response and refining the positions and relative locations.
It is nowhere near as simple as your friend suggests.
all that would be left is flooring
That's simple: In your case, it looks like you have a good concrete slab floor in your room, so you are already done!
That's about the best floor you can get, acoustically. Polish it, stain it, or whatever other treatment you'd like, and that's all you need. Or if you don't like concrete, then just lay ordinary laminate flooring directly over that, on a suitable underlay.
But the floor is usually the last thing you do in a studio, so if you do want laminate, don't do it yet. Just leave it as concrete until everything else is in place.
if I should have light fixtures on the roof or just go with a floor lamp or something?
You can go either way. You can't embed anything into the ceiling, of course! But you can use surface-mount fixtures, in places that won't be covered up by the ceiling treatment. Personally, I prefer to put at least some of the lighting in the cloud itself, as you can see in the photos in that link above. I often also do concealed lighting above the or below the treatment devices. There are many options.
I should mention I do have a bunch of bass traps and treatment already for the room, something like 16 panels.
How do you know if they are the correct devices for the room?

You can't just throw any old bit of acoustic treatment into any old position in the room, especially for a mastering suite! The treatment needs to be specifically designed, and specifically located, to treat the specific issues that the room has.
All of the above assumes that the room is already isolated correctly, but that doesn't seem to be the case from the photos. Master suites need to be very quiet inside (NC-20 or lower), which implies very good isolation. The electrical panel on the wall, single in-winging door, and the simple 2x4 plywood ceiling suggest that the room is not isolated at all! It seems to be just a plain old room. If that's the case, then before you can do anything else you need to figure out your isolation. Building the isolation system is going to shrink the room by many inches on each side, and only then can you think about room geometry, layout, and treatment.
The other major issue that you seem to be forgetting is HVAC: There are no registers anywhere in that room, so it can't be used like that for a professional mixing or mastering suite. HVAC is a big issue in studios, and is an absolute necessity. It often takes me as long to design the HVAC system for a studio as it does to do the entire structural design and acoustic design together! It's a big deal.
Any and all help if greatly appreciated!
My advice would be to re-think this from the beginning: The normal method for planning a studio starts with a clear definition of purpose and goals, which includes deciding on the level of isolation that will be needed (in decibels: how many decibels of sound attenuation do your walls, floor, ceiling, windows, doors, HVAC, and electrical system need to supply? Once you know that, everything else starts to fall into place: you can determine what type of isolation walls and air gap you will need, which determines the final dimensions of the room interior, which in turn determines what the modal response will look like, which determines the type, sizes and locations of the base traps as well as the correct positions, layout and geometry for the speakers and mix position, which once again determines the locations for the initial basic treatment. It's a process, a sequence, that you need to follow to get from where you are to where you want to be. Once you get the room built to that stage (initial treatment already in place), then you can measure the actual acoustic response of the room, compare the results to what it should be, and design the next level of treatment.
- Stuart -