It's been awhile since I looked at Kilimanjaro as an objective, but I believe it's one of those places that climbing without a guide is prohibited. Most guiding services do a cursory if not thorough screening of their clients' medical disorders prior to embarking. It is possible that
A. They already have experience with mental health and altitude and can give you some insight
or
B. They have a list of disorders that are an absolute no-go and that schizophrenia is on it.
I'm genuinely intrigued. Please let us know what you discover.
My initial reaction to your post was to wonder which would be more stressful: hiking Kilimanjaro or traveling (alone?) in Egypt and Kenya? If you really feel capable of an extended trip through multiple foreign countries, my hunch would be that a well-organized trip up the mountain wouldn't be much riskier. Just a thought.
PS - You didn't mention how long you haven't been taking meds. If it's been a few months, that would seem very risky to me. If it's been years, your chances of success probably go up.