PP is spot on. I've expressed the same misgivings in previous less elegant posts. Te'o's story doesn't pass the smell test.
The problem is that no explanation of the facts passes the smell test. The best one I can come up with is this:
I think that Te'o was duped, but that he was guilty of playing games, too. I think that Kekua was more of an acquaintance than a girlfriend to him, and that he used the relationship because it was convenient, and amused him. I think he made lots of calls because he was trying to be a good guy and help in her time of need, but really didn't feel any particular obligation to visit. Over time they probably did become closer, from all the contact. Then, when she "died" at the same time as his grandmother, it did mess with his head, but then the story took on a life of its own, and the nature of the relationship expanded beyond what it ever had really been, and he didn't object. Why bother, after all, she'd dead, right?
When she called again on December 6th, he was pissed, because he thought she was playing games with his emotions (she was, but not the ones he thought). When she kept calling, he finally went to his coach - he still thought she was real, but by this time thought she was a real pain who was trying to play head games with him, and just wished she would go away, and didn't know what to do The PI report confused him more, because it tied her to Tuiasosopo, but then, he knew they were tied together. At this point he knew something was fishy, but he didn't know what, exactly. Still thinking she was real, he didn't know what to do? Do you hold a press conference and say "Well, you know that girl I thought was dead? I guess she faked it, but at this point i wish she was dead."? It wasn't until he read the Deadspin report that he finally understood - she indeed had never existed at all.
Now, meanwhile, What was Tuiasosopo's goal? I have no clue. I think he started it as a prank, and it was for his amusement. Somewhere along the line he needed a girl play the part of Kekua, and then things got out of hand. I have a funny feeling that out there somewhere is a real girl that developed a real crush on Te'o somewhere along the way, and the 'prank' took on a life of it's own. I have another sneaking suspicion that this girl can't come forward and admit that for some specific reason, such as, she may be under age.
As for Reagan Mauia? I have no clue where he fits in. Maybe he's the second guy that assisted Tuiasosopo, and opened his mouth before he realized it was far, far too late to save the scam.
So, there is my best guess...feel free to shoot holes in my theory. Every other theory has holes, and mine probably has plenty, too.