Question reg. AC21/H1B/EAD/AP

[speddi]

I am posting this on behalf of my friend who is unable to post on IV for some reason.

His email quote:

I have my H1-B valid until 2009, but the visa expired. I applied for I-485/EAD/AP. Got EAD card and AP document. I don't intend to use EAD at all, until unless absolutely necessary. Being on H1-B until we get GC is important, since I want to have a backup, in case renewing AP/EAD is delayed, and also renewing driver's license is based on H1-B/EAD validity. I intend to travel outside US, and return back using the AP. I don't want to get my visa stamped, as its a hassle, and getting an visa appointment is a hassle as well.

My questions:
1. If I travel outside US and return, and use the Advance Parole at the port of entry, what are the restrictions on my H1-B status?
2. Can I be on H1-B with the present company?
3. My H1-B will be in 6th year in 2009. Can I extend it beyond that to be on H1-B beyond 6th year (when I use AP)?
4. Can I change jobs on H1-B (to a different company).

Any other restrictions, problems associated with using Advance Parole, when I intend to be on H1-B (and not use EAD)?

I think the answers to the questions are
1. No restrictions
2. Yes
3. Yes
4. Yes

but would like to get expert advise.

Thank you.