Can some person/lawyer/entity file a citizen's petition and delay any possible approval?
If a CP is filed whose sole purpose in the view of the FDA is to delay an ANDA or 505b2 NDA, the petitioners may be subject to fines or other penalties.
Are there new rules regarding CPs regarding timelines and disclosures?
The FDA must disclose a CP and must rule on it within 180 days, unless the requests in the CP are moot pending the outcome of litigation. (An example of a moot CP is the one filed by Teva in 2008 regarding the NVS/MNTA ANDA for Copaxone.)
They are available within a few days of being filed. You can get them in person or online. Often the "citizen" filing the petition is a law firm, and it may not indicate which company paid them to petition.
I don't have the specific link at hand for online access, but check these sites: