Building a system with non-Zeiss optics on a Zeiss stand is theoretically possible, but not something I recommend. While you can use non-Zeiss objectives and matching non-Zeiss eyepieces on this stand without excessive trouble, the real problems come when you need to, for example:
- adapt non-Zeiss condensers to fit and work on this stand
- find non-Zeiss DIC prisms, phase annuli etc that work with the non-Zeiss objectives of your choice and fit at the proper reciprocal distances in the condenser or stand sliders
- make the built-in Zeiss telan lenses play well with the non-Zeiss objectives and eyepieces. The original telan lenses are quite likely to delaminate, by the way, and finding third-party ones that fit and work in this stand is not a child's play, so you may be forced to live without telan - it is possible, but why would you voluntarily make your life more difficult?
Everything becomes a lot easier if the stand is mechanically compatible with all the other parts you intend to use.