(I won't spoiler this since I thinks it's barely related to what the episode was about, but feel free to edit me if it is not so)
I saw this interesting theory regarding Applejack
Quote:
1. Applejack subtly implying that it’ll be Granny Smith who’s absent from the next family reunion.
2. The exact timing of WHEN you see the two shooting stars, compared to what Applejack was saying.
3. I feel like Applejack’s behavior during the episode arose from her not being over her parents’ deaths, as well as her anxiety towards the approaching inevitability of Granny Smith’s death.
4. Actually I think this might be behind Applejack’s workaholic attitude as a whole.
5. Granny Smith and Applebloom are close to their cousins. Applejack doesn’t seem to like Braeburn very much.
6. Of the three siblings, Applebloom is the most talkative. She’s also the only one that wouldn’t remember her parents.
7. The lack of photos of Applejack’s parents — Nayuki confirmed that the portrait on the wall wasn’t them.
My new headcanon is that Applejack NEVER got over her parents’ deaths, and couldn’t even cope with it. She buries herself in her work to hide her feelings, and while she is affectionate and protective of her family, she’s also emotionally distant.
Applejack has never had a mental breakdown scene because she’s ALWAYS broken down, mentally.
That is quite depressing, but it certainly clicks with what is shown so far.
Now that Applejack's parents are confirmed dead, I have a theory about Rainbow Dash's parents. It's very strange that her parents hasn't been mentioned so far. They weren't there when she entered the best young flier competition. When she was hospitalized, they didn't visit or even send a get well card. On Dash's side, she care a lot of about getting attention, and seem to have a fear of being alone (Mare Do Well, May the Best Pet Win). Because of that, I believe Rainbow Dash's parents are either dead, or very neglecting.
Actually, with Fluttershy and especially Scootaloo's parents have also not been shown, it is possible that pegasus possess bird-like behaviour, which means as soon as the foal reach the fledging age, they are on their own (not all bird species behave like this, but it seems to be common).