I agree that the unit roster is a bit thin, but I think your proposed additions are extremely overpowered for their price. Your cavalry also do so many things in so many ways that it will be difficult for players to remember and apply all of the small bonuses.
Here’s how I would write a cavalry unit:
Cost: 4 ipcs
Movement: 2 (no blitz)
When attacking in a battle where your opponent has only infantry defending, your cavalry attack at 4 instead of 2.
These cavalry would shine in Kazakh or in Africa, where artillery are real thin on the ground, but would not be cost effective in “higher-tech” areas like France, where trenches and enemy artillery could shred cavalry before those cavalry could reach their desrination.
I’m not sure what kind of army your field artillery are supposed to represent, or what kind of thematic gap they’re supposed to fill. Can you say more about your vision for them?