Well, I honestly don´t think I hold any authority on these matters but I´ll answer to the best of my knowledge:
I applied for both prelim and categorical positions at every single program I applied to (37 or 38 not sure). As I said before, I got seven interviews and three of the programs were very clear in saying they were interviewing me only for a preliminary position; still, I always asked during the interviews, just to see if I could charm them into reconsidering, which of course didn't happen. Of the other four, two specifically said in the invitation letter that they were interviewing me for a categorical position and in the other two I had to ask their secretary/coordinator for clarification.
Having said that, it is something that always came up in the interviews, and I dont personally think is shows weakness, rather it shows you are smart enough to be aware of the fact that you're playing against the odds and that your trying to increase your chances to the max. I don´t think there is point in trying to "hide" this disadvantage we clearly have, it´s a fact and the PDs know it, I think bringing it up yourself during the interviews (if pertinent), also shows you´re mature and and it does get a little bit of the awkwardeness out of the way; if anything it shows you're confident enough on the strenght of your application to discuss it openly.
As for the ranking, again I´m not sure, but I ranked the categorical programs first and then the preliminary ones, starting after the lowest of my categorical options.
This is my opinion based only on my own experience, if I had to give dome advice I would say that the best thing you can do know is kick some serious rear-end during your first couple of months in the program you´ll start in june and get strong letters for the next season, otherwise your profile sounds great, I believe that (for IMGs) usmle scores and US letters are probably the most important piece of the application. I certainly wish the best of luck.
Also, i hope you guys are right about my email meaning I got a categorical spot, otherwise i´ll be feeling not so good at noon on thursday. It said: "Congratulations! You have matched."