Good Evening Flatface:
To the best of my knowledge no, once back pension stops and he/she is back on the pay roll.
Your second question I would believe if he/she has not attained the 35 years they would have to keep contributing until 35 years of service is attained.
As far as benefits are concerned would someone more knowledgeable comment on this please?
With reference to the first two answers would someone confirm that as I have no information to back this up?