Can you use command link drone + squadron redeployment to immobilize and move out a dreadnought? Or is only use to move tau units ..

Well, Squadron Redeployment can be used on non-Tau units, but it cannot be used to exhaust and move a unit that you do not control. The reason is that exhausting the unit is a cost of the event. You are not allowed to pay costs with cards, resources, etc. that are not yours.

Thanks