Is there a dimmer that would control a combination of 2 incandescent recessed cans and a set of cable lights with a magnetic transformer

A magnetic LV dimmer will do the job. They are OK for Magnetic LV and standard Incandescent. If I remember right, they block DC current that would otherwise heat up the magnetic transformer primary.

Lutron should have what you are looking for.

Don't the low voltage dimmers from Lutron require a neutral. There is no neutral at either three way location

Neutral is required for "Electronic" lv dimmers not magnetic