I made a blogpost about the updated Changeling canon after S7E17 "To Change a Changeling".
If anyone is interested you find it here.
Below is a copy.

In S7E17 "To Change a Changeling" Thorax used an flashback to explain Pharynx's behavior, revealing more canon information about Changelings.
(Note: I will limit this post to the "original" Changelings; the new reformed Changelings aka Changedlings won't be mentioned here.)
(Note: For other information of this subject see Attachment C.)

• Every young Changeling wanted to be an "aggressive warrior type". Different opinions were mocked. Exceptions were rare, but existed. (Thorax rather played with dolls and was picked on for that. Pharynx stood up to protect him from the others.)
• Young Changelings are playing/training by destroying plush figures of ponies. (Including ripping of the head. But how would they feed on them afterwards?)
• Young Changelings have access to information about foreign non-pony species. (Thorax plays with a doll of an baby dragon. He made it probably himself, since it looks kind of makeshift and noling else would have make the doll for him.)
• Young Changelings already can transform. Even in complex beings far bigger than themselves. See Attachment B.
• Young Changelings can already fly; small distances confirmed.
• The green eggs (?) hanging from the ceiling seem tho shake sometimes on their own.
• It is possible for normal drones to have different colors. See Attachment A. (This is seemingly extremely rare, since we had seen it only a single time. The purpose/reason for that in unknown; assuming there is even one except for making him easier to spot in the show.)

Attachment A: Pharynx' colors, and how the differ from the usual Changeling color sheme.

• Eyes: lavender exept for the normal blue.
• Wings + upper Carapace: a darker blue/lavender instead the light blue; wings still transparent.
• Tail: red instead of grey.
• Hair/Finn (when grown up): red instead of grey/black.

Attachment B: Thoughts and Speculations about Pharynx' transformation.
The being Pharynx transforms into was at least 6 times as big as Pharynx himself. This contracts the theory Changelings can only transform into beings/objects around their own size and weight; assuming his abilities are comparable to the average Changeling.
Additionally it is in my opinion unlikely Pharynx had seen the creature he had transformed into himself, since he would live inside the protected nusery. He had probably only heard about it or seen pictures (can/do Changelings even draw?) or he simply imagined it.

Attachment C: Other sorces of Information.

• Expanded canon after S6E16 "The Times They Are a Changeling"
• Expanded canon after S6E25+26 "To Where and Back Again 1+2"
• The Changeling Research Group

Nice notes.