I would say calipers, but if you don't have access to any, posting your pics here and asking for BF% estimation can be somewhat accurate. Unless you have a very high BF%
Saw a really small(no muscles) guy doing 1/8th squats on the smith machine. Before I saw him do it I was like : WTH, he squats 100lb more than me and must be 60 lbs lighter. But then I saw he was...
It is very easy to get 150g + of protein a day. I was on a calorie deficit diet and managed to get 150-170g protein everyday, as well with a good amount of carbohydrates.