No interview, but no decision?

[sysbiol]

I've gotten an acceptance for what I'm pretty sure is my top choice school, among a few others, but I still haven't heard anything from Brown (MCB) or Yale (BBS MCGD).  I didn't get invited to interview at either, but I also haven't gotten a rejection notification.  I'm 99% sure a rejection is coming from both, which I am OK with, because I admittedly didn't put the same level of effort into their application processes (contacting PIs, etc.) as I did for others.  But a few people are telling me this means I might be waitlisted or something, though I'm not sure why considering I didn't even interview.

Multiple faculty I interviewed with/had significant contact with at the program I am interested in at my 'top' school have reached out to me both before and after the official acceptance email, saying they hope I attend.  I don't know if this is normal but it seems that it didn't happen for the graduate students in my current lab.  I'm feeling a ton of pressure to accept immediately although I don't think that is their intention -- I'm just anxious as hell with this whole process.  I can't decide if accepting the offer now would reduce my anxiety levels, or if making the "permanent" decision would raise them exponentially.  Super conflicted between just getting it over with and accepting in an attempt to calm myself down, or waiting it out.  It feels irresponsible/premature to take an offer without having all of the official decisions in hand.  I emailed the main graduate admissions offices at Brown and Yale this week, and got an automated form response from Yale directing me to FAQ, etc.  The office at Brown responded directly and I will hopefully hear from the departmental administrator soon as well.  

Has anyone managed to get a decision out of either Brown or Yale before they posted it to the online application portal/sent the official email?  Did you call or email them? And did you contact the main grad admissions or the individual department/program? Or, do you guys think it's a waste of time to chase it considering I wasn't invited to interview?