Does anyone have quick sample code in C# to add a Node in NPM using this SDK?
The issue was resolved in NPM 10.3. It is independent of the SDK version.
Because of a technical issue with the WSDL, Visual Studio's "Add Service Reference" process generates a client that won't actually work for creating a node. This issue has been addressed for the release in development now. Until then, I recommend you use PowerShell for creating nodes. If you'd like, you can drive PowerShell from C# - it has an extensive API for this.
Do you know if this issue has been resolved in Orion SDK 1.5?
Do you have a concise sample of how to add nodes using powershell or over the API?
For using in C# you don't need Orion SDK, however if you don't mind about programming language and powershell is sufficient for you, install Orion SDK, there's a sample how to add a node, just open Orion SDK.pdf included and look for chapter Adding a Node for Monitoring.