Hi Nick,
  Glad to see that you want to preserve old family equipment. I think it makes  all the time and work put into it extra meaningful....but, Boy! If you get everything that you have listed up and running, you will have been one busy individual!
 As to where to get parts, there are many sources such as Maibach, Korves, your local AGCO dealer, Lynch Farms, and many others that I can't think of at the moment. There is reproduction sheet metal, wiring harnesses and the like plus tons of engine parts. 
   As far as technical support, this site is the greatest. There are folks here that have many years of Oliver experience and will gladly work with you on something that gets you stumped....just post it.
    I sure would like to see what pictures you may have. Ask Chris Losey to set up an album for you. Once he does, you can add pictures any time.
      Give me some time and I can look up some of those ser.# and give you their year of manufacture....perhaps someone will beat me to it.
There are lots of good books on Oliver equipment out there and another place you will want to get to know is the Floyd County Museum which will have all the manuals for your equipment. Manuals are a must if you get into the repair of any of your equipment. Good luck!
                                               Cal