Opportunity to work from India for the same company

[Sandeepsk15]

Here’s my situation and my questions:

- on H1b with an approved i140 priority date Jane 2011
- h1b valid until March 2019
- I am moving to Indian branch of my company for 2 years 
- will be on the payroll of the Indian branch
- plan to move back to the US after 2 years

Question:

- I might have to travel on work back to the US in the next year. Will I need a different visa like B1? 
- when I want to come back after 2 years, will my h1b still be valid because of the remaining time I had on it? or will i need to com on L1 or some other visa?
- what happens to my Green Card application? I am hoping it stays alive, right?
- Do I need to and can I renew my h1b even though I am not here?

Thanks!