Best practices for stable product dev env

I'm sorry if this the wrong forum for this question and if so, please advise where best place to go for this question is. I'm also going to apologize in advance for not having down how all of these systems interact as I've tried to impose software version control on my project but have failed to be able to maintain any sort of consistent dev environment to date.

Background:
I'm developing a commercial app using vive trackers and the product may sometimes leverage an HMD depending on the use case so sometimes it will need full vive support. I have all of this sorted out. However, I have been burned (3rd degree) twice now in the last 6 months by updates in the steamvr plugin. I need to lock things down so that I can create a stable Unity/SteamVR stack for my app. I'm looking for best practices on how to create a stable Unity development environment based on the 2018.1 4 Unity Editor LTS and OpenVR V1.4.8.

Questions:
How do you lock down the Unity Plug In version? Do you have to make a default Unity project and just keep it around as a directory copy for a template?

StreamVR V1.4.8: I can download the git dist but I'm a little confused about how to stick it under Unity. Sorry if that sounds stupid but I'm not sure how to manage OpenVR independent of Unity's SteamVR plugin. If I select the Unity 2018.1.4 LTS version, does that contain a stable version of OpenVR based on a specific version?

My sincere thanks for any advice.