Wow, where to start?  I'm confused as to what I'm supposed to take away from your comments.  Your discomfort - at funding public art, this specific project, artists asked to provide credentials and expected to act professionally, artistic inspiration in general?

Most professional artists should also be considered design professionals.  Their art requires the generation of an idea and then a plan of how best to manifest that idea within a certain time frame, budget and materials limitation.  This idea can come from within, but it is equally valid if it assigned by others.  This is no different than how an architect, composer or graphic artist has to work.  So it seems only natural to give artists the same respect of inviting them to participate in the project.  

Secondly, good public art is disciplined hard work, and most artists who would respond to this RFP are excited by the challenge of interpreting the design parameters through their unique way of working.  

Thirdly, when a visual artist has a gallery or museum show for example, he or she usually has to produce some kind of credentials so that the curator knows the artist can deliver on providing enough work for the exhibition which is usually scheduled months or even years out.  This  requirement is not a problem for serious artists.

I use the term serious artist for someone who defines themselves professionally as an artist in the same way an attorney, carpenter, or dentist defines their position in their business - meaning they get up in the morning and that is what they do.  They are not amateurs or hobbyists; they go to their workspace and have work to get done.  The artists you mentioned are serious or we wouldn't know of them, but how can you possibly know what inspired Thomas Cole et al  unless you knew them personally and heard the premises of their work.  You state "But art ... is provoked by something beyond oneself." How is the scope of this project not from beyond the artist?  

Just some thoughts provoked by your questions...