Yes surely u can go with pcmb as u can do well in the field of ur interest. And as far as jee is concerned anyhow physics and chem are common to both jee as well as neet so it won't be much difficult. 

yup.it is a very good idea.go ahead dear

It's totally upon you to select what you want to do. If you have good interest on Biology, then you should take it. It would need a little more hard work. But Biology is an easily scoring subject.