Spoiler
1. Do you think it works better to try and collect different characters or various versions of favorite characters? Both?
In the short term, I think it's fine to collect up as many variants as you want, if you're only going to be in to the line for a year or so, you can sell them off to other collectors as your interest wanes. In the long term I think it's much better to keep diversifying the herd. Especially with G4 brushables, the base pony is quite boring when you don't like the character. They can change hair, add paint and accessories, but overall there's only one pose and the main appeal is the look of the pony, and a small herd with variety will be more exciting than a large herd made up of only four characters looking slightly different. Having a little army of a pony you're passionate about can be a fun addition to the herd though, and sometimes the variants of a well-loved pony can keep your interest ticking over until the next OC.
2. Do you feel that any particular type of pony collectibles are more enjoyable? (Brushables? Mini figures? Funko?)
Mini figures and POP serve those with limited space/money, and fashion styles serve those who love big ponies with big hair for the styling element. I think the widest appeal lies in the brushables and the Funkos. Brushables for those who like ponies as playable, styling toys, and Funkos for those who are very invested in the FiM show and want dead-on accuracy without worrying too much about functionality.
3. Since it was the cartoon that got me into these G4 ponies (I believe that's the term?) does it stand to reason that I should check out the original cartoon to see if it connects me to G1? I never had the chance to watch it as a kid--there was big time competition for TV cartoon time and I had two brothers. :)
The G1 cartoon I find very enjoyable, but it's not for everyone. If you really enjoyed the first two episodes of FiM and other 80s kids media appeals to you, give it a shot. I'd recommend the first special (Rescue at Midnight Castle) to almost anyone just because it has ponies fighting back against a giant magical centaur version of satan, what's not to love?
4. Where do you think playsets fit into collecting pony stuff? Are they as important as the ponies? Are they worth it for a new collector?
Playsets can be fun additions, but there would be no use for them without the ponies, so I think ponies are more important. A lot of people don't have the space or money for the extra plastic, and if you don't want play or dynamic display, they're pretty useless. G4 playsets 2013 and before, I'd say a general no as to worth... There are all of two castles and the rest is all accessory packs or vehicles like cars and train sets. No rooms for ponies to sit inside, barely a building faceplate here or there. Now is actually the best time to be in G4 if you love playsets, as we've recently gotten the POP sweet shoppe and the upcoming Canterlot Castle is very detailed. I might be biased because I adore the G1 playsets like the Show Stable, Dream Castle and Paradise Estate, which are huuuge set pieces, highly detailed and with actual roofs and walls for ponies to exist within. Now that's a play set!
5. (This may seem a weird question, but...) What do people DO with the ponies? I mainly owned barbies and action figures growing up. I never really understood the ponies (as stated earlier) so I'm curious what their allure is as toys. (To me they're TV characters at this point.)
Personally I love playing with my ponies. I like to carry them about the house and pose them wherever I'm sitting. I make up personalities for them and put them into families and friendships and partnerships, and then make up adventures involving various members of the herd. I also like to add cute accessories like ribbons, barrettes, hats, shoes, saddles, etc. Sometimes you need to relax, lie on the couch, grab a pegasus and make them jump and trot around the cushions and fly from seat to seat. :P They're simple little creatures, but I always liked animals best, when I was younger I had stuffed animals and Barbie horses as the prizes of my toybox.
6. Where does Equestria Girls fit into the whole pony thing? I saw the first movie and thought it was 'okay'. I've heard the second one is better. I'm kinda torn on these--I collect Monster High and these would fit in... But I'm not sure whether I'd display them with the Monsters or the Ponies? (Again, I realize there's no real definitive answer here.)
It's just like MH and EAH. MLP FiM was out first for a few years, and then a side line was introduced as EQG, and one of the cast went through a magic mirror and had adventures in the new universe to connect the two audiences. Sooo, as to whether you'd display them together or separate, it's your choice. Both are branded MLP and come from Hasbro, the same as both M/EA are branded "High" and come from Mattel. Would you put MH Fright-Mares with the MH or the MLP shelves?
7. What do you think is currently the MLP item to have? It doesn't necessarily mean I'll want / need it; I just think it would be fun to know what others are hunting for. :)
Right now we're in transition between the old Rainbow Power line and the new Cutie Mark Magic line. Some of the later RP releases are getting spotty releases and are harder to find, and desirable because they contain new characters/versions/rereleases that everyone's been looking forward to. Fashion Style Applejack and Daisy Dreams, Rainbow Neon brushable Holly Dash, Rainbow Shimmer (snowglobe) ponies of the four princesses are probably the most sought after at this point. Also within the new Cutie Mark Magic line are new characters and as they haven't hit everywhere yet they're still flying off the shelves - CMM brushables Sweetie Drops and Skywishes, Charm Wings Honey Rays, and Water Cuties (snowglobe) ponies especially Diamond Mint.
8. If there was one piece of advice someone could have given you when you decided to collect ponies (or even toys in general), what would it have been? That question may make sense or may seem strange. I'm not sure how many kept collecting from childhood vs. returned to this later in life. (I did that with dolls.)
Only collect what you like. Don't feel pressured to collect everything or to be completionist - just stick to what really excites you and feels like you can't do without. Don't buy as an investment because anything mass-produced will be worthless as soon as the craze dies or most of the enthuasists move on. And if you don't want something that you have, move it on as soon as possible! Toy collecting causes enough clutter, don't allow useless stuff to just sit around your house. One person's trash is another person's treasure, and one person's perception of treasure causes them to part with their money... ;)