All of these are cheap HG's.
The Gundam Barbatos will be blue and grey and I'll find a nice gun for him or give him the Kimaris/Graze Ritter long sword. He looks all Father-Knightish.
The Jesta will be green and tan drab and will go to Haqqislam. Because I don't have any giant bug mechs, I'll go with a giant soldier looking guy. I will keep the gun with a giant pointless red dot site and the shoulder shield with rocket things. I may plant a conspicuous combat kife on him, such as the curved kukri-style knife that comes with the Reconguista Grimoire.
The Amida custom Hyakuren will be bright neon orange with dark rich green and grey trim as it looks kind of like a bigger, weirder old school Guijia sort of thing. It will keep the gun that comes exclusive to the kit and the cool sword thing.
The Hyakuri will have no rocket back pack and will have some bits to cover the holes in the shoulders. It will be black grey and red in a quasi-Bakunin style. I may give it the IBO grenade launcher or the snub nosed graze machine gun. I may also give it a standard heat hawk from a zaku.
I may use the Hi-Mock (Gundam Build Fighters try)
and Man-Rhodi (Gundam Iron blooded orphans) as Mercenary suits.
I will also use some Robotech Tactics RPG regult pods as smaller high speed security TAG's as they are big enough for an Infinity infantry figure to scrunch inside.