1- does it have junos os per devices models,( say SRX3400, srx 240, EX 8208, Mx, j series router )
eg. on high end SRX 3400, mpls is not supported but it is on low end SRX 240. can you confirm something like that?
The virtual devices are not exact replacements for specific models. They are a virtual specifc version of the product line with their own nuances in features for example vSRX/Firefly. For feature support see the matrix in documentation.