Arguments/reasons for them actually being Red's emotions

2MuchOfAFangirl said Yellow might have refereed to himself as a child and a kid because he was just created

Blue and Yellow get upset if they are called Red they probably all see each other as real people

Blue may have mentioned his "mom" in an attempt to nurture himself. He also speaks in the third person and likes to hide away from people

When Green mentioned their mom it may have just been Preston messing up

They probably call each other siblings because they've gotten used to each other

Originally Red felt sorry for Magenta saying poor soul, then he said she was a science project and showed no real remorse. The last time Magenta was mentioned was in a livestream when he saw a Magenta skin and said we don't care about Magenta. This may be because over time they got over her dying since they never knew her.

As for why Red could turn into Blue in Do Not Laugh and Two Truths and a Lie

Red and Blue may have temporarily refused into one being.

As for the whole Gray situation he saw a fanmade Vacktor skin that was gray and looked evil he may have just made a little joke about the skin

This might also explain why Red asked Green if they should keep Blue around

Spooky Tales could just be another universe

Purple may not even be using mind control. Red, Blue, and Yellow may still have parts of Purple in them. Or because Magenta was innocence and she died they became darker. Or Red may have never taught them right from wrong. Though they do seem to have common knowledge of things...

Might explain why Adam mentioned the Legend of Shifter. He may have known what Red's intent was

Yellow sometimes makes these uh uh uh sounds. It happened when he accidentally killed the chicken egg and in slow fast when he did not guess the sound correctly. This could be that Yellow was feeling sadness and had no idea how to process it. However, the other Vacktors including Yellow have shown/felt other emotions before.

Maybe this is why Yellow won't talk about Purple claiming he will "change" he may not want to be sad. He was sad when he accidentally killed Pikachu p, but quickly snapped out of it. Or maybe he will change into Blue? He did tell Adam he doesn't change colors, but he could have been lying to protect himself. I mean Red turned into Blue in Two Truth's and a Lie.

Pink may be able to feel emotions more because shes a state of being

Green is probably disgust but Red probably did not want to make it sound too much like Inside Out

Also I'm convinced Red is a fan of Inside Out

Although Red did admit the timeline/Vacktor logic was messed up

And we learned Roommates season 3 was a screen production

So I guess its up to whatever people want it to be :/

There are many reasons/arguments as to why they are his emotions, but there are just as many as to why they aren't

I personally go with the they are his siblings theory but thats just me

Also Red said he reads books when he is sad. Blue is apparently his sorrow/sadness, but he fears books. Did Blue maybe also get fear as well? Also in Yellow's room there is a bookshelf. Did Yellow get Red's love of books? I mean Yellow does seem nerdy talking about historical events, Star Trek, Lord of the Rings

(My mind made me think about these last night)

(Also it's October and I'm messing that I can't go back and rewatch Spooky Tales)