I sort of remember some of the info from distant memory (considered what you are about to do, once) but I found this:
http://www.peachparts.com/shopforum/diesel-discussion/325014-converting-240d-300d-turbo.html
Which will be more accurate than my memory....
On the heater hose: you may be right about where the hose connects to the OM616 block, but as far as I remember the hose on both cars runs to the same place on the firewall, so you'll just need good OM617 hose. Is that what you meant?