[@Rydude17] I probably worded something incorrectly but I was trying to imply that they are not well known by the general public outside of areas where they may be geographically present. Almost certainly some people would know of them. Alternatively, maybe they could be mistaken as a sub-species of the lizard folk if they are around as well?

Although, similar to your first suggestion I could borrow more from the source material in the Cthulhu Mythos where they are basically plotting the same thing. In a nutshell they were the dominant species on Earth prior to Humans millions of years ago but eventually suffered a decline following wars with several other species including Humans. Eventually the remnants retreated underground, the majority of which are hibernating in pods filled with life extending chemicals. They generally hate or resent Humanity feeling that they are blocking their rightful re-ascendance to power. There are a few agents disguised within society, probably to learn about the culture and seek weaknesses to exploit, and some may even hold positions of power. Something like this might make an interesting plot point somewhere. 

As for the second point, yeah. The tail probably wouldn't follow him in a straight line in the back but somewhat coiled around him. As a result, he would often have a generous amount of space between him and anyone around him lest they trip over 'nothing'.