Thank you all for your feedback!
I did watch the armor build video last weekend - so many great tips and instructions! I have so much more confidence now going into the armor build part of this project.
And now with the helpful pointers above, I've finished my flight suit. Per Chopper's feedback, I rounded off the top corners of the front patches, and thanks to BikeScout007's clarification, I raised the bottom of both patches up so that they end about 2.25 inches above the top of my kneecap.
I almost forgot about the elastic straps (I went with 2 inches wide for level 2) - that's why they were not part of my initial photos. Good thing I remembered before sewing on the suede. Per the supplied reference photo, I positioned the straps so that the vertical center is at the halfway point between the bottom of where my belt is going to sit and my knee.
In preparation for attaching the suede patches, I seam ripped the inseam, butt seam, and the front seam between the zipper and the inseam. Then I sewed the elastic ends under where the suede will go and pinned it in place just outside the patch area so it wouldn't move on me. I made the strap length so that when the suit is worn, the straps would sit against my leg just tight enough so that there is no slack.
On to the suede - I'm so lucky to have the only Tandy in Michigan less than a half hour from my house. I bought a pigskin soft suede split (in black, of course). With the patterns efficiently placed, I had enough for all of the thigh patches and plenty of extra for the butt flap (which will come later, after I build my belt).
Instead of just sewing on the patches and hoping they didn't move (the suede is to too thick for pins), I opted to follow what f3tt4l1f3 did in his incredibly helpful photo-filled tutorial within the undersuit mods tutorial - Heat n Bond! I used this to stick the patches on the suit so they would stay in place while I sewed them around just inside the perimeter to the suit and seam allowances. Never mind the wet spots, that was just me removing the chalk lines since I didn't need them anymore at this point.
The next part was kind of a nightmare. I sewed the seams I ripped back together. The part between the zipper and the inseam in particular! With the added double suede thickness, my sewing machine wasn't particularly happy with me, even with the leather needle, by it trudged on like a champ. Again, not being able to use pins was frustrating, but I have some really great sewing clips that saved the day here.
So now, here is the finished suit laying on the bed and with me wearing it. Hopefully it's good since I did the patch preview before sewing! Oh, and I hemmed the pants too, so now they're not too long.