Are Sigma auto focus 28-90 &100-300 from Pentax mz 60 slr combatible with latest Pentax DSLR?

Answer 1

Yes, as Pentax has never changed its mount since switching from screw fit to bayonet fit lenses (the only major marque so to do). All that will happen if you use the lenses you mention is that the focal lengths will increase by about 50%, so 28-90mm will = (approx) 42-135mm and the 100-300mm will = (approx) 150-450mm