Since it was filed early, namely, before April 1, USCIS can reject it and return your packet back to your attorney. However, since it was a weekend, they may consider it as filed on next business day which is April 1. There is no clear answer to your question.
Considering that USCIS will consider petitions filed all week towards a tentative lottery, you may not know until next week how they proceeded with your petition. In addition, duplicate filing is not permitted; your employer...
The USCIS may visit the bona fides of marriage when you apply for naturalization since you got your green card through marriage to USC. Divorce, by itself, does not automatically cause termination of residency.
If the time allotted by the CBP Officer is insufficient, you may want to apply for an extension. Consult with an experienced immigration attorney regarding the feasibility of seeking more time for tourism.
If H-1B is approved in your behalf in the past six years, you may not be subject to the cap.
If the current petition is filed seeking change of status and it is approved, you are required to join your H-1B employer. If it is rejected or denied, you may continue in L-1 as long as it remains valid.
Whether L-1B visa in your passport will remain or will be cancelled upon grant of H-1B will depend on the USCIS officer. It is not automatically cancelled.