1. No, it only complicates matters.
2. Cannot be determined from your posting. That would depend on the background of the candidate.
3. You choose the employer you wish to work for BEFORE there are any filings, and have that, and only that, employer file an H-1B petition.
Your employer needs to retain an experienced immigration lawyer to review all the facts, advise them, and handle the case. Your employer can find one through http://www.ailalawyer.com.
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.
1) No. It is best to choose and have only 1-2 companies petition for you. Remember you will be questioned at the Consulate towards this bona fide job offer and your bona fide intent to join your petitioning employer. Petitioning companies spend thousands of dollars on these petitions.
2) No. However you may be questioned during visa interview regarding the multiple filings.
3) As mentioned, wisely choose an employment opportunity with a good company, may be two, and have them petition in your behalf.
This response is general in nature and cannot be construed as legal advice, given that not enough facts are known. Any comments offered on Avvo are of a general nature only, and are not meant to create an attorney-client relationship. If you would like additional information based on this response, please contact my office at 510 657 7665 or 415 902 0832 to schedule a consultation.