I am very interested in using my inheritance to get into REI. 

I have been fortunate that the rental buildings I have purchased so far have been either empty or had great long term tenants. I am now buying a duplex from Auction.com and am trying to get a hold of the current lease...

In all of the lots, we are only inheriting one home that will be owned by the park which we will be working with the current long term tenant in place to see if they would like to purchase the home.  

Since he was one who inherited the property, we are confused as to whether he will owe no capital gains tax because he inherited, will he owe tax on 75% of the proceeds.

Many of those potential buyers will not want to inherit the problem and will walk away.

You do not say if these are inherited or ones you screened and accepted as tenants.

1) depending on when the FTB lien was recorded will determine it's priority.2) What will happen is that the successful bidder on the 1st TD, or for that matter any lien ( all liens are jr. to property taxes) the new owner of record via trustees deed will inherit the existing property tax liability. 

I had inherited window units in some of my wall sleeves that needed to be replaced. 

I've heard in the podcasts that they usually have problems with tenants they inherit; if I wanted to remove all existing tenants from a purchased fourplex, do I have the previous owner notify/remove tenants as terms of the sale? 

Also,tell the seller you want the property delivered vacant before you pay him a nickel.Cat lady being evicted is his problem,not yours.Find out what the West Virginia laws are and have him give her the 30 or 60 day notice to leave the state requires ASAP to prevent further delays.Remember,you must put "Seller must deliver property vacant at close of escrow" in the contract so you don't inherit his negligence of a freeloading tenant who's apt is probably a disaster area to be completely gutted.