Why would Minionese be a combination of Spanish, English, and many other different languages? It's due to the fact that they have served masters across the world.
The main Minions: Kevin, Stuart, and Bob parallel Margo, Edith, and Agnes, respectively.
Kevin and Margo: The eldest, tallest, snarkiest, protective over the youngest/smallest, The Leader of the group.
Stuart and Edith: The middle child, enjoy destruction, the impulsive one of the trio, sometimes gets annoyed with the youngest, The Lancer of the group.
Bob and Agnes: The youngest/smallest, has a stuffed animal companion, the most naive and kind-hearted of the trio, The Chick/The Heart of the group.
This analogy's Fridge Brilliance is multiplied when you consider that part of the reason Gru developed such strong feelings for the girls, despite his reluctance, could be that they reminded him of his three most endearing individual Minions.
Scarlet Overkill, described as the first ever female supervillain, certainly had to work a lot to be adored this much. After all, the 60s are when the feminist movement really kicked in and women began trying to become equal to men. This also means Scarlet had to work a lot more to get recognition, and perhaps her extreme measures (she is called Overkill, after all) were the way she found to get said recognition. She didn't have another choice but to be more brutal, more dangerous and more heartless to gain this title... and thus pave the way for every female supervillain that exists in the Despicable Me universe.
This also explains why despite being the most popular supervillain, Scarlet was looking for minions in the beginning. She explicitly states that women were believed incapable of robbing a bank, with that kind of mindset (which wasn't unheard of in the 1960s), a lot of villains, (male or female) wouldn't deem working for a female supervillain great choice. So, Scarlet had to reach the top so no one would underestimate her.
Walter Jr. and Margo = Oldest and tallest of the children. However, while Margo is quite smart, Jr. isn't exactly...all there.
Tina and Edith = Middle child and love destruction. However, Edith is more reserved and tomboyish; Tina is a girly Genki Girl.
Baby Joe and Agnes: The youngest child. Baby Joe is quiet and growing into a villain; Agnes is the most excitable of her siblings and will probably grow into a proper hero (as seen in the short, "Training Wheels").
Look at Scarlet's plane: It's basically an upside-down "S".
It's often brought up that the Minions only come back to humankind after the Second World War. The theory that surfaces is that the Minions would have followed Hitler, were they not in their icy cave for all this time. There's another explanation: If the Minions had been a part of the Third Reich, history would have been rewritten drastically. We know plenty about the World Wars, but we have fewer records of anything before the 20th century, which means it's much easier to add the Minions into these historical situations. There's more leeway.
If Scarlet had just rewarded the minions fairly for giving her the throne of England, then in all probability her reign would have been secure and she would have been queen for the rest of her life. There's An Aesop in that...
Scarlet may very possibly be an Audience Surrogate. Surely, many parents dragged into the cinema could relate to her burning declarations of hate for the Minions at the end of the film. Particularly, her disgust upon seeing the entire Minion tribe, not unlike parents being bombarded with merchandise to buy their kids.
Scarlet flipping out at her Minions comes off as hypocritical given that they are a bunch of idiots. However, in the Despicable Me universe, the villains are generally rivals constantly trying to one-up each other. Scarlet may have seen their actions as trying to betray her and take her position as top villain.
Even if she saw theyd made a honest mistake, that wouldnt really be better. An incompetent underling, no matter how loyal, can only be tolerated to a limit and then they become a pain and an embarrassment. If Scarlet wasnt going to kill the Minions for treachery, shed have killed them for messing up her coronation.
The Minions always follow someone who is the most evil, which is usually someone who has defeated/killed their last boss. So, what if Gru gets defeated by someone who doesn't have a Hidden Heart of Gold like our favorite protagonist does? Even after 42 years of friendship?
This could be slightly averted, as if this were true, the Minions would be submitting to Vector from the first movie and El Macho from the second movie (even then, Dr. Nefario turned on Gru and his minions temporarily). The point is also further driven to when Gru softens down as well. However, if Gru were to die ...
It probably won't happen because the creators will want the Minions staying with the Gru family.
The Minions clearly don't care about serving the most evil villain by the second movie. Gru's a legitimate businessman and they still work for him. If he died, they'd default leadership to Lucy or one of his kids.
It's also quite possible that the Minions aren't especially interested in "evil" as much as "badass and authoritative", since they're quite willing to follow a dinosaur and Napoleon, neither of whom are portrayed as supervillains (and "evil" in the Despicable Me universe seems to be used as a buzzword for "roguish-but-lovable mischief" in any case; even in the first film, the most evil characters were otherwise normal people like Miss Hattie). In addition, while naïve, they still won't serve someone who's openly hostile to them. Gru may no longer be a supervillain, but he's still the coolest guy they know, and anyone who would harm him would probably harm the minions themselves.
If they are interested in evil, it does seem rather horrific that creatures would be biologically driven to help the most evil person they can find. Just think, they might have ended up helping Hitler (or should we wish they had tried, with their incompetence?) This is probably why the movie keeps the Minions in the cave from Napoleon's time to the present.
Actually, watching back, I noticed something: Every boss the minions had, they chose to follow.
Looks like Herb suffocated to death in that ice at the end. Scarlet's mouth is free but not his (or his nose).
Then again, Herb is perfectly willing to (try to) torture innocent creatures. Has he done so before?
Vector's head got frozen in the first movie to no ill effect. Presumably, complete freezing halts all biological processes.
Remember when we saw a younger Mr Perkins cheering Scarlet? How on Earth did he go from a fanboy of a supervillain to the ruthless banker he is in the first film?
It wouldn't be that big a step, he may have been inspired by her.