Using IronPython with Unity 5.2

So I've been trying to get IronPython to work with Unity 5.2 such that I can call external IP scripts from within a scene to be executed (in this case, mapgen scripts which enable modding by the user).

I've read basically every post there is to read about this subject, but I'm struggling a litle. I've got multiple versions of IronPython - for .NET 2.0, 3.5, 4.0 and 4.5 all ready to go with associated Microsoft libraries.

The 2.0 version, when adding the relevant .dll files to Projects/Assets/Plugins/Resources/ gives me compatability errors with .NET 3.5, so I assume that's the version to be using.

When using .NET 3.5 the scripts themselves compile perfectly within Visual Studio but my scene won't run and my project won't build within the Unity editor with the following error (see below). Googling for this error gives me a lot of quite vague answers that aren't very specific or imply problems within the DLLs themselves, but that isn't really something I can control in this case.

Any ideas?

Error message is at http://pastebin.com/6meVdiLz as it's quite huge.