No this shouldn’t impact them at all for citizenship.

Yes you may but I864 may be better.

Yes it is best to include previously issued documents to aid in decision.

Yes as long as you have a validly issued extension.

Most likely within 30-90 days of request.

Selected as the best answer

As long as spouse is otherwise adjustment eligible, you may be able to petition as LPR. Consult with an attorney for guidance.

May be more worthwhile to petition for their permanent residency.

Yes that individual is eligible to be a sponsor.

Yes you may do so with the I130 pending.

No while not advised, you should not be penalized.