Mane 6 first statistics

Here's a list of the first time any of the Mane 6 do a number of notable things.

Of course, with the possibility of Starlight Glimmer becoming a main character, I might be keeping my eyes open for her doing all, except the first on my list, though I know she'll never find her way onto two of them even if she is the main focus of Season 6. (And I'm not talking about the ones directly related to Seasons 4 and 5)

Let's start off with having their own song (even if others sing along for a part of it in at least one case), and not counting human counterparts

1. Pinkie Pie - Friendship is Magic Part 2 (The Laughter Song)
2. Rarity - Suited for Success (Art of the Dress)
3. Fluttershy - The Cutie Mark Chronicles (So Many Wonders) Though chronologically she'd be the first
4. Twilight Sparkle - A Canterlot Wedding Part 2 (Big Brother, Best Friend Forever)
5. Applejack - The Last Roundup (Raise This Barn)
6. Rainbow Dash - Tanks for the Memories (I'll Fly)

If we're counting Starlight Glimmer here, which I won't until we have confirmation she is a main character, it would be The Cutie Map Part 1 (In Our Town).

Next, the first time time the pony has an episode revolving around them, not counting episodes shared with another pony, that pony has to be the main character of an episode even if there is focus on one as a secondary protagonist:

1. Twilight Sparkle - Friendship is Magic Part 1
2. Applejack - Applebuck Season
3. Pinkie Pie - Griffon the Brush Off (unless you count it as a Pinkie/Rainbow episode but after Gilda comes in it's clear the episode centers more on Pinkie)
4. Fluttershy - Dragonshy
5. Rarity - Suited for Success
6. Rainbow Dash - Sonic Rainboom

Now, for something people find adorable about the ponies - Squee! (I never kept track of all of them so I did some research)

1. Twilight Sparkle - Feeling Pinkie Keen
2. Fluttershy - Stare Master
3. Rarity - Green Isn't Your Color (hard to notice)
4. Pinkie Pie - Green Isn't Your Color
5. Rainbow Dash - Read It and Weep
6. Applejack - A Canterlot Wedding Part 1

And now for another thing people find adorable about the ponies - blushing. (Again I never kept track of it before so I've been doing research by checking every image with the word "blush" in its title so if there are any that don't, please let me know)

1. Fluttershy - The Ticket Master
2. Twilight Sparkle - Boast Busters
3. Rarity - Green Isn't Your Color
4. Rainbow Dash - The Mysterious Mare Do Well
5. Applejack - The Last Roundup
6. Pinkie Pie - The One Where Pinkie Pie Knows

Note: Rarity's first blush and her first squee come in the same episode! It's an angry blush, but it still counts.

Now for writing a friendship report to Princess Celestia! (Note: It has to be written to her, and not counting the one the other Mane 5 do together in Lesson Zero or else they'd all be tied for second). In this case I'm allowing Rarity's friendship report that's shared with Sweetie Belle

1. Twilight Sparkle - The Ticket Master
2. Rarity - Sisterhooves Social
3. Rainbow Dash - May the Best Pet Win
4. Pinkie Pie - Baby Cakes
5. Applejack - The Last Roundup
6. Fluttershy - Putting Your Hoof Down

And now for their name appearing in the title of an episode:

1. Pinkie Pie - Feeling Pinkie Keen
2. Fluttershy - Hurricane Fluttershy
3. Rarity - Rarity Takes Manehattan
4. Rainbow Dash - Rainbow Falls
5. Twilight Sparkle - Twilight Time

I do not think Applejack's name has appeared in a title yet, even though the word "Apple" has

Now for a one-time thing - Getting their keys in Season 4!

1. Rarity - Rarity Takes Manehattan (Coco Pommel)
2. Rainbow Dash - Rainbow Falls (Spitfire)
3. Pinkie Pie - Pinkie Pride (Cheese Sandwich)
4. Fluttershy - It Ain't Easy Being Breezies (Seabreeze)
5. Applejack - Leap of Faith (Silver Shill)
6. Twilight Sparkle - Twilight's Kingdom Part 2 (Discord)

And then the map episodes, which involves the ponies being paired together:

1. Rainbow Dash and Pinkie Pie - The Lost Treasure of Griffonstone
2. Applejack and Rarity - Made in Manehattan
3. Twilight Sparkle and Fluttershy - The Hooffields and McColts

Warning: The next two that come relate to something that some users here are annoyed by me talking about, so if you don't want to hear it, do not read past this point. If it gets enough negative reviews I will remove it.

Biting tails:

1. Applejack - Friendship is Magic Part 1 (Rainbow Dash)
2. Fluttershy - Friendship is Magic Part 2 (Rarity)
3. Rainbow Dash - Friendship is Magic Part 2 (Twilight Sparkle)
4. Twilight Sparkle - Feeling Pinkie Keen (Pinkie Pie)
5. Pinkie Pie - A Dog and Pony Show (Fluttershy)
6. Rarity - Putting Your Hoof Down (Fluttershy)

Biting their tails:

1. Rainbow Dash - Friendship is Magic Part 1 (Applejack)
2. Rarity - Friendship is Magic Part 2 (Fluttershy)
3. Twilight Sparkle - Friendship is Magic Part 2 (Rainbow Dash)
4. Applejack - Fall Weather Friends (Spike; for Mane 6, Rainbow Dash)
5. Pinkie Pie - Feeling Pinkie Keen (Gummy; for Mane 6, Twilight Sparkle)
6. Fluttershy - A Dog and Pony Show (Pinkie Pie)

And yes, for both Pinkie and Applejack it's in the same episodes