Solid cam questions.

The shape of the lobes are different between hydraulic cams and solid cams. Since there needs to be some clearance in the valve train a solid cam has a shallow ramp to take up the clearance gradually that's not in a hydraulic cam.

There's likely some people that have mixed lifter types on cams but it's not going to have a long life if you do.

If you have pump up problems why not purchase anti-pump up lifters. You will need to have an adjustable rocker to use them, but you will need that to go to a solid cam anyway.