Welcome to the forums!
for your last one, the right hand is a little bit too low and the left foot is inside the box while in the reference it is outside of the box 
so far your drawing over the models is off to a pretty good start tho some of them are a little flat so try to think about how it would curve rather than how it looks initially.
the lower ones are pretty good in terms of the curves tho.
haha yes post them! 
the people here are really nice and will give you good feedback they won't be too harsh about it but will simply kindly point things out but ultimately its up to you if you wanna incorporate the critique so post freely and there's no pressure if you don't post in a while too.
I used to post every day but then i got busy with life 
and at the moment i have other priorities besides my personal project and art school so i might only just post once a week or once every few weeks or really just whenever. I take inspiration from @Vonschlippe who is really good at drawing, yet it is a hobby and he posts when he can and if not then whatevs but everytime he posts its just super amazing
And don't worry about not being good enough, we all start from somewhere! Also its good to post even if its bad, so that as you go along the course, you can look back and say wow look how much better i got compared to the beginning! (tho that can take time so don't rush urself). most important thing is to have fun!
