You can find out the assignment information for issued patents and published applications through the USPTO database at http://assignments.uspto.gov/assignments/?db=pat. If the application has not yet been published, this information is not available on-line. And there is always a risk that the applicant did not fully disclose his or her obligations, which would presumably be a violation of your contract to have the application assigned to you.
Provisional applications are not published, and frequently not formally assigned even if there is an obligation to assign. If a provisional application is not turned into a patent application, usually by filing a utility patent application within a year of the provisional filing date, claiming benefit of the provisional application, the provisional application goes abandoned and information regarding it will not be publically available other than as provided under MPEP 711.04 Public Access to Abandoned Applications: “Access to an abandoned unpublished application may be provided to any person if a written request for access is submitted, and the abandoned application is identified or relied upon: (A) in a U.S. patent application publication or patent; (B) in statutory invention registration; or (C) in an international application that is published in accordance with PCT Article 21(2).
Igor did a great job of answering most of your questions above. However, it may be helpful to clarify that the USPTO only has assignment information for what people have explicitly recorded with the USPTO. There may be unrecorded assignments, obligations to assign and licenses that have yet to be recorded that may still be in force, and navigating these may be problematic. If you do have concerns, it would be worth having an attorney review the details before licensing/paying for a patent.
1. Recorded transfers of ownership (referred to as "assignments") of issued patents and of published patent applications are accessible via the USPTO website. See the link I've provided below.
2. Yes. Sometimes an inventor is subject to multiple obligations, as when a professor is obligated to assign his inventions to his university, and when he acts as a consultant, he also is obligated to assign his inventions to the company he consults for. Such a dispute is currently before the U.S. Supreme Court wherein Stanford University is battling with the Roche companies over ownership of patent rights for an aspect of the molecular biology technique called PCR. See the 2nd link below.
3. A provisional U.S. patent application remains in the permanent records of the USPTO.
However if it is not referred to publicly (such as in a published nonprovisional patent application that claims the benefit of the filing date of the provisional application) it isn't accessible to the public. Only the applicant or his designee would be entitled to access it.
This posting is intended for general education and isn't "legal advice." It doesn't create or evidence an attorney-client relationship. You are encouraged to engage an attorney in the pertinent jurisdiction for confidential legal advice on matters of any importance.
My colleagues have done a good job answering your question regarding the provisional patent application.
But I doubt very seriously that you can rely on the USPTO data base to obtain all of the information you need to ascertain whether a pending patent application was appropriately assigned to you. it is quite common for there to be conflicting claims of ownership in an invention, and the issue of whether an invention is owned by an individual inventor and/or a univerisity or private corporation is often hotly contested. Generally speaking, if an individual did the work leading to his invention while employed by a private company, the company owns the invention, and the individual has no right to assign it to another person or company. Similarly, most universities and academic institutions have formal policies about ownership of inventions created by professors or graduate students while using university facilities---and often the university is the owner of any resulting patent rights. Before accepting an assignment from an individual inventor, it is a very good idea to retain counsel to investigate the issue of whether the individual inventor had the right to assign this invention to you---often time individual inventors (former employees or college professors) are mistaken in their belief that they own the invention. Chances are the the USPTO will not have the information necessaryt o resolve this issue.