Simple RAW for 5e 4: Smackdown v. RAW

[Windwaert]

Q148a
Does the Manta Glide of the Animal Enhancement feature of Simic Hybrids grant 'movement' while falling?

Manta Glide: Your ray-like wings can slow your fall and allow you to glide. When you fall and aren't incapacitated, you can subtract up to 100 feet from the fall when calculating falling damage, and you can move up to 2 feet horizontally for every 1 foot you descend.

Note that Relentless Avenger feature of the Vengeance Paladin uses a somewhat comparable phrasing of "... you can move ..." and then refers to "This movement ..."

Q148b
If so, can this 'movement' from Manta Glide be spend on standing up from prone instead?

Standing up takes more effort; doing so costs an amount of Movement equal to half your speed. For example, if your speed is 30 feet, you must spend 15 feet of Movement to stand up. You can’t stand up if you don’t have enough Movement left or if your speed is 0. To move while prone, you must crawl or use magic such as teleportation.