Which ships will be able to transport the Ballista? Will a mechanic be in place to cable-lift them with, for example, the ARGO MPUV or using a tractor beam (kind of like how tanks can be transported via helicopter)?

As it stands, there are only two ship series specifically designed to transport the Ballista - the Idris and the Hercules (by transport, we mean getting it entirely inside the vehicle, properly secured, and doors closed). While not officially designed to carry the Ballista, the 890 Jump's rear cargo ramp is large enough to take it too. Ships equipped with a suitably powerful tractor beam will also be able to move it, but this comes with a higher risk than having it secured internally.