Congratulations! seems you've taken easily to lucid dreaming.

The issues you mention seem to be dream control issues...things that improve with experience.

I;ve felt my body and dream body simultaneously. I put it down to simply being close to waking up/sleeping lightly. However, this is the sort of thing liable to change everytime. Sometimes you may feel your body, other times not. Im not sure you can change this?

To stop dreaming...without waking up? Why would you want to!?
try
- spinning fast with your eyes shut.
- going to sleep IN the dream
those are my best ideas.

As for that eyes thing....Id say once again you were just sleeping slighty. Maybe you should try to stabilise the dream. These sorts of techniques my help 'hold you in the dream' more.

-inspect/feel your hands upon becoming Lucid. Really investigate them up close. Concentrate on the look and feel.
-dont dive into exciting activites STRAIGHT AWAY
-do reality checks even after you know you are dreaming

just some personal tips. sorry, after re-reading it was a particularly unhelpful reply! lol I tried