SPOILERS Saints Row 4 Morph And Homies Mod

DOn't really know myself but it seems that using Fan of Saints Sandbox+ makes it work because :
I did it with success in the cribs but crashed one time outside .
I just tried and I got the same results as you: the morphs work only inside the crib. But I haven't been able to morph into npcs which already didn't work with the normal version of sandbox+.
Basicly 2 ways
Mech version - Broken head and half good anims
Open homies.xbtl and find the mech homie
Replace the model to eg: NPC_Shaundi
Second way:
Use Rastaman's SR3_City that allows you to switch to gat (And few other character aswell) others seem to crash