Lightroom and Photoshop do not share the Camera Raw plug-ins. The Camera Raw code used by Lightroom is baked into Lightroom.
Using the most recent PS and ACR will not be a problem as long as you do not try to use cameras not supported by LR 6.1.1.
In addition to what ManiacJoe has said, Lightroom is a complete standalone software application. It does not require you to have any other other Adobe product installed on your computer. Lightroom CC2015.1.1/ 6.1.1 has the equivalent processing engine as ACR Plugin 9.1.1.
The latest PS CC application will have ACR Plugin 9.2.1 and will therefore be fine if you use the "edit in" function in LR 6.1.1 to send a raw file to PS CC for further editing.
Thank you very much to both of you, it's perfectly clear now for me : )