H1B transfer and expiring I94

[CanadianJeff 22]

Looking for some clarification on H1B transfers and how I94 expiry dates factor in.

 

Currently working for EMP-A under a multi-entry H1B which is set to expire June 30 (I was hired on a one year contract and plan to complete the full year with EMP-A).  The I94 is also set to expire June 30. This is my first year in the USA.

I now have EMP-B who has requested I join their company. EMP-B is flexible on start date.

 

My questions are:

1. Can EMP-B apply for a H1B transfer if my current H1B is set to expire before my planned start date with EMP- B?

2. Are there any significant differences between a transfer and a new H1B application? If I understand correctly new H1B may be subject to caps whereas transfers are cap exempt. 

3. Is is necessary that I start with with EMP-B before the H1B and I94 expire? For example, if I planned to start work with EMP-B in August (which would be after the current H1B and I94 expire) would this introduce any new challenges with the H1B transfer?

4. If my H1B transfer is successful, how do I extend my I94 expiry date?

5. I will be returning to Canada for a short period in April. When I return in April and reenter under the H1B should i expect my I94 to be extended beyond June 30 or is it likely to be set to match the date of the H1B expiry?