Hi. When it comes time to take rendered sequences from LRT and stitch them together into a "movie" what file type and/or settings do you guys recommend...particularly for showing the movie on Facebook/youtube style platforms to best effect?

For direct upload to platforms, I recommend MP4, force 16:9, Standard Gamut, 1080p, Quality Medium or High.
Mostly the output of LRT will however be used as Master for further video editing (cutting, adding music etc.) in a Video Editor.
In that case, I recommend rendering in Prores (LRT Pro) or MP4 (Private/Free) in High Quality and choosing appropriate export settings from the video editor then.