I'll answer some things even though they've already been addressed. This is coming from a long-time Pokemon fan who owns and plays every title in the series. Baw, so I'm a nerd, wanna fight about it? XP Kidding.
Anyhow, questions first.
1) They mentioned something about EVs and how you need to grind endlessly for hours against the same enemies endlessly to make your party as strong as they possibly can be. Is that all really necessary?
No. I didn't care about EVs for a long time and recently just started caring because I got bored and wanted something to do. Now I like picking Natures and whatnot. Adds another layer to the game. Having additional strengths and weaknesses allows you to think about your team more, if that's what you want. But you can be perfectly happy ignoring them too. I think the 5th Generation (Black and White) is exceedingly easier than other games in Pokemon. What with being able to use TMs like HMs now, among many other things.
2) Is it possible to fill out the pokedex if I don't have all the previous generations to import from?
Not really. Just like usual, you need a friend to Trade with, or other games from previous Generations. There is additional content that you can do now called 'Dream World' over the Internet that allows you to get Pokemon you would otherwise not be able to get.
3) Should I start with B&W, or is B&W2 an okay spot to start? From my understanding, BW2 actually continues the story from 1?
Honestly, I don't think this matter. I think the storyline from Black and White 2 is pretty crappy. To me, it doesn't feel like Pokemon any more. They brought things in that made me face-palm rather than enjoy. However, if you still care deeply about storylines, I would start with the first iteration. Because there are some extra things you can do with 2 if you have completed the first one. If you don't care so much, I would start with 2 because it has superior game mechanics and additions that make the game last longer with more fun value. It just doesn't come from the story (for me).
That being said, I would go along with most people and recommend starting with the remake of Silver and Gold. Definitely my favorite game of the entire franchise.
4) This is honestly really important to me. My first even pokemon was a Charmander, and Abra's final form was my main heavy hitter back in the day, battling my buddies. Are those guys still around? Would I be able to get them in my party without owning older games and importing?
Abra is available, I believe. Charmander, not so much. Which is a shame. If you were to own one of the copies that I have, I wouldn't mind Trading with you, though. I have a complete Pokedex on Black and White.
Now. I have a lot of snarliness when it comes to the newest Generation. A lot of issues come from the Pokemon. Which just don't FEEL like Pokemon any more. If you take any one of them and put them beside something of the first or second Generation, you KNOW that it doesn't look right. Save for a handful of Pokemon, the rest look like ugly, horrible, rip-off Pokemon. Among the worst being a veiny Pokemon with a two-by-four, a GARBAGE BAG, an ice cream cone, and gears. Yes, gears. The Legendaries are also hugely disappointing in design and function for me as well. It doesn't feel like they are trying any more. This is part of the reason that I recommend Heart Gold or Soul Silver. You don't have to deal with any of that crap, or Triple Battles which are horribly useless.
A lot of people would argue or say that everything's fine. But I don't think so. I can count off the new Pokemon I like with the fingers on two hands and not use them all. Anyways, I am sure you'll make your decision based on what is important to YOU. :) That's just all of my input. Been a Pokemon fan since day 1 and will always continue to be one. No matter how many awfully design choices they throw in there.