Franch

I have no idea about Lato, but Jet Stream does affect Latron Incarnon projectiles, which is releveant to this topic.

The +45% Fire Rate for Secondary Weapons bonus from Amalgam Furax Body Count increases Dex Pixia Prime fire rate in the arsenal, but does not affect it in missions.

The Latron weapon series cannot equip Terminal Velocity, but the Latron Incarnon is a projectile weapon. The Quellor is a hitscan weapon which has a projectile alt-fire and it can equip the mod, so this seems to be an oversight.