Question [Q] [Help!] Video chat to answer lots of questions, general and device specific?

Hello! First off, thanks for having an awesome website like this, and forums full of help!

So as the thread title states, I'm looking for someone to video chat with so I can ask a bunch of questions. I am a slow reader, and have some eye strain issues, so I tend to avoid reading like the plague; so looking through lots of forum threads for each piece of information isn't a great option for me. The other reason why a vid-Q&A session would help me is because I really am pretty ignorant on most of this fancy cell-phone type of stuff, and may have a huge range of questions, from basic definitions, to device-specific possibilities, to program choices, etc. I don't do well learning stuff from reading, and am much more of a discussion-learner. Also, typing back-and-forth is also very time consuming, so I'm not huge on that sort q&a either (though obviously, if someone's willing to spend time helping me out, I'm appreciative of whatever way they help). Finally, the big crunch factor is time. I have 6 days to return this device, and I think I'll need more time than that (due to my schedule) to figure everything out on my own forum-searching. So I'm humbly asking if someone is available and willing to spend their time to make my work easier. I'd be greatly appreciative!

I need someone who speaks English. I'm in the Eastern time zone (US East coast). Please PM me if you're able to help!

Some of my question topics:
I bought a 'new' T-Mobile Galaxy S3 T999. But I'm seeing indications that the device is rooted or something. True?

Is my device disabled from downloading any updates, or just an issue with Samsung holding the current update?

The Root Explorer app shows all options in some oriental language. Is there a way to change that?

***When dialing to make a call, my older phone would allow me to search by name (so I'd hit 5646 and anyone named John, and other possible names would show up as options). My new phone doesn't do this, and I don't see an option anywhere for it. Is there a simple way to change this? (This is the question which started my search in the first place, bringing me here).

All Galaxy S3s are basically the same hardware? The only difference really in how things play out is the programming/OS?

My device has 4.1.2 T999UVDMD5. I read (here: that this OS is pretty crappy, and he's happy with the one he replaced it with. I need help figuring out whether switching up my OS is right for me, or no. I do see some lag in performance, and a bit of quick battery eating. Also not so happy with minor changes to the keyboard.

Where can I find layman's definitions of terms that people are throwing around? Like ROM, Firmware, Flashing, Odin, Kernel, etc. I assume that if I'm going to mess with my phone, I should know these things.

If all phones are created equal, and can be stripped down and dressed back up to function as desired, would it make more sense to return my $350 new S3 (non-contract), and buy a used one in good condition from Swappa for $200-300, and rework it?

Is buying from swappa safe? Seems kinda sketchy to me, in terms of reliability for returning a product if needed.

Like I said, lots of questions all over the place. Thanks in advance for reading and any help you can give! (especially to any tech guru's who aren't camera shy.