It is even more important to check out a Rav or Rebbetzin than a shadchan. If you go to meet a shadchan and she turns out to be a lousy shadchan, no major harm has been done – just an annoying experience to turn into a funny story for your next date.
On the other hand, an unqualified Rav can do a lot of harm.
It can be harder to check though. What you really need to do is to find a mainstream Orthodox community to become part of so that you will have more resources.
I would think it would be a good idea for you to find a bt seminary to learn in, but perhaps that is not an option for you.
In any case, what you should probably be doing right now is to just keep learning and researching and thinking things through and discussing things with people (whether in the CR or RL) and thinking through their responses and opinions until you are able to figure these things out and figure out the best Rabbanim to go to.
I think these are the questions you should ask yourself about a potential Rav: Does he follow the Gedolei Hador? Does he seem like someone who has Yiras Shamayim? Are there a lot of people who seem to consider him to be controversial? Is he accepted by many b’nei Torah? Does he seem either too authoritarian or too liberal? Does he get too involved in your personal life and/or tell you what to do regarding personal matters that you didn’t ask him about? Do other Rabbanim accept him? Is he normal and well-balanced?
I think that at this point you should probably not restrict yourself to one Rav, since it will take you time to figure out who a qualified Rav is. I think you may need to “test the waters” with several Rabbanim for now.
I have a relative who is a giyores. She told me that before she converted, she was told that she had to move to Brooklyn in order to see what mainstream Orthodoxy was like before she converted. I think that it would be a good idea for you to move to somewhere similar so that you could have more of a feel of mainstream Orthodoxy and develop more resources.
btw, I am impressed at how you do always seem to be going to shiurim and asking questions and keeping an open mind and trying to figure things out. You seem like you are on a good path. Hatzlacha with the rest of the journey!