As a Hem/Onc Coordinator privy to the deliberations of our faculty over the ROL I want to pitch my two cents in here:
*My PD will respond to any thank you letter received and respond positively regardless of whether you will be ranked high or low. My PD and faculty also do not discuss ranking with applicants, it's officially frowned upon so it's a matter of professionalism not to ask nor offer.
*If they are interested in you coming to their program the PD or other faculty may reach out unsolicited to you via a phone call or email, this is a very good indication that they are in fact interested in you and you will be ranked.
*We don't rank all candidates, there's usually a batch of people for one reason or another that get put on the Do Not Rank list. It usually has more to do with personality than anything else.
*Applicants invited to interview are generally on par with each other at least on paper so it becomes a matter of determining whether the person would be a good fit for the program.
*If you were invited to interview there's a reason you were invited, PDs (or at least my PD) will invite anyone who meets our basic criteria; good LORs, good USMLE scores (and we DO look at the step 3 scores) and a good personal statement.
*Research experience is very important, especially if you are looking for a scholarly track.
*Visas matter, H1Bs are very expensive for programs to support, programs are taking an expensive risk when they support an H1B. J1s are better but keep in mind that only Permanent Residents and Citizens can be placed on a training grant so research funding is tighter for any visa holder.
I think I hit most of the big questions I saw floating through this thread..
Oh, PS: Updating Frieda is a mess so when in doubt refer to the NRMP as that's the only one that matters.
As applicants we are so desperate to hear any word from programs and we might consider any kind of communication as a positive feedback! for example I know someone who is an IMG. One program sent him an email to make sure that he will be only on J1 and not H1 since they started ranking, and he was so excited about that email!! Another friend of mine, she got a generic email from a program asking to make sure that applicants should make sure that they are registered in NRMP since they started ranking, and also she was so excited about that email!!
Many faculty of different programs know each other and can find out if they want. Unless they had a gun to my head and asked, I wouldn't go that far! 
