I know muscle weighs more than fat. As I continue to loose fat I'm also gaining muscle which weighs more than fat. Water might fluctuate my weight a little day to day, but it will be temporary loss or temporary gain. At some point, when I have more muscle than fat (my body fat index is low right now but lean muscle measurements are not where I want it to be yet) how will I know what's muslce weight, what's fat weight, what's water weight and how much fat is still to be lost?

I would use a waist size measurement. Set a goal to loose maybe 2 inches or so. BMI isnt that accurate because it doesnt calculate