IMO, a DC motor wire drive idea is a non-starter, it will be far more difficult than using a stepper motor since you need to integrate motor speed with a high degree of accuracy to turn that information into length. This would require an encoder to have any reasonable accuracy.
A stepper, along with a knurled drive wheel of a certain diameter, will have a direct relationship between the number of step pulses issued and the resulting length. A two hundred step motor with 15.91mm diameter wheel will yield 0.25mm wire length per step. You can increase that resolution by microstepping, using a higher step count motor or a smaller diameter wheel. There will be a balance required between maximum speed desired, motor torque, measuring wheel size and resolution.
Stripping can be any number of ways. The obvious is a hinged set of notched blades similar to a basic hand stripper that cut the insulation then with the blades still closed, pull the insulation off in the downstream direction with the blades. You'll need a set of secondary pinch rolls downstream of the stripper to hold and eject the wire after the cut to length and then strip the newly exposed end of the cut wire in the upstream direction. Eject the cut and stripped wire and the process repeats.