Portland Tenant law question

[Chris Gibbs]

I recently closed on my first triplex in Gresham OR.  All three units are on month to month leases and I decided which one I was going to move into.  Before closing I asked the seller to give the tenant a 60 day no-cause eviction so that I could move in within my 60 day window of closing (fha financing).  He agreed and mailed the document which I have a copy of.  Now the tenant seems to think that because the property changed hands that the 60 day he was given before is not valid.  I cant find anything in the tenant laws about this kind of situation.  Does anyone here know if I need to do anything in addition to what has already been done by the previous landlord?  I know now that I could have given him a 30 day after we closed but since he already got the 60 day I didn't bother.  Should I give him a 30 day tomorrow?  Or do I have grounds to have him out by the 30th of this month via the previous notice?

He also seems to think that he is due 3 months rent for being forced out of his residence (completely not true).  All of this is pretty confusing and I do not know if I am missing something or he is just trying to scam me for more money/stay longer.  

Thanks for all your help in advance.