L1B to H1B COS through external vendor


My H1B petition is approved , but my L1B to H1B COS transfer didnt happen , because when my H1B was getting processed I had gone out of states (in July). The employer who is holding my H1B, plans to file for another COS which will happen by November last week 2013.

I have to again go back to India in Jan 2014. My question is whether I can apply for L1 to H1 COS through my employer once I have come back from India instead of getting COS in Nov 2014 , or will USCIS raise any question that why COS didnt happen for so long.

If my COS has happened , then during visa interview for H1 stamping in Jan (when I m in India) how can I prove to the interviewer that I m working for a genuine employer. Given the fact that I will have only Nov and Dec. pay slips with me.

Also, if I feel that I’m not working for a genuine employer, can I get my H1B transfer done to another better genuine employer ? If yes, can it happen with the help of less than 3 pay stubs?