There is some name mangling that happens in order to make C#-imported files be compatible with Haxe. You can check them out by running `haxe -cs dummy --no-output -D dump=pretty -net-lib path/to/dll` . This will create a directory called `dump` where you can find all classes as they are seen by Haxe.
In the second case, SingleInstance, type parameters get a `_<number of type parameters>` suffix. So you can access it through the name `SingleInstance_1<>`
You don't need to import the dll name; Rather, you just need to know which namespace they were defined. All namespaces are lower-cased, so if you have MyNamespace.Other.SingleInstance, you can access it through the path mynamespace.other.SingleInstance_1