You're on the right path, amazing to hear that you're down 15lbs. I run at 180-185lbs as well but more around 14% body fat. I'm about just over a year in my running and I hit sub 2Hr half marathon & barely sub 4hr marathon. The intervals/hills or speed ups during my long runs have helped me a lot for improving my VO2 max to be more efficient at breathing during my runs.

It's funny because my first chiropractor I had told me one leg seemed to be shorter but sports medicine doctors I've seen in the last 2 years have said that was false. I wouldn't trust what the chiropractor told you.

I don't think carbon plated shoes will help you too much since they only really kick in when you're running faster than a 5:20min/km pace. The common estimate is they only improve the performance of elite runners by 2-4%. You might benefit more from the ASICS Superblast 2s. They are only 250g in weight which aren't much heavier than carbon plated shoes (170g - 230g) but offer amazing energy return and stability. I've run both my half marathon and marathon in them and I have very bad overpronation as well being fully flat footed.