L1 and Green Card in EB1 category

[usatocanada]

I have been working in US on H1B. Recently me and my wife moved to Vancouver, Canada for my wife's job. My employer in US wants to retain me, so they are working out how they can employ me in Vancouver. I still have a few questions related to US immigration:

 

H1B

1. If my company employs me in Vancouver, Canada, do they have to revoke H1B petition?
2. If I want to come back to US after a few years, do I need to go through the lottery again? 
   1. I got H1B in 2014 and it is valid until Sep, 2019. Does answer to previous question change based on when I want to come back? Example: Before Oct, 2020? or After Oct, 2020?

Green Card

1. If I remain employed in Vancouver, Canada for 2-3 years, can I come back to US on L1? Is there any condition that must be fulfilled for my employment in Canada? 
2. I can become Engineering Manager or Engineering Director, if I remain in this company for next 1-2 years. What would be more beneficial for me: Coming back on L1 or coming back on H1B?
3. I am originally from India. If I go through regular Green Card processing, it will take 15-20 years to get Green Card. I have read that for managers there is different category and it takes close to 2 years to get Green Card (EB1?). I also read that EB1 for managers/execs is only applicable to L1. Is that correct?
4. What are the conditions that must be fulfilled to get Green Card in EB1 category for L1? 

[Provence]

Does your multinational employer have a legal team? 

It's usually a good idea to get in touch with HR/legal. They have access to your academic profile and work experience, and would suggest the most viable option going forward. Bear in mind these are employer-initiated petitions. Employers do the legwork to bring a foreign national employee based on a job posting for which a US worker is not available.