How should you respond to the solid Ruy Lopez opening as the black pieces?

Thank you for your in-depth response CM_grandmasterjunior, this will prompt me to look deeper into these lines. Since I began this forum, I have learned a decent amount about this opening that I had not previously known; however, even so, some of these variations I had not seen before. This gives me a nice study topic  I especially appreciate the effort put forth in noting some lines to look into (and I glanced at them all), but really the only way to fully understand the position is to simply sit down and study it first-hand. I will spend some time looking into these lines, but I thank you for the springboard I can use to dive into this theory, as well as the time you have taken to present this.

Why don't you try switching to Italian? The opening is much more open, where you can get more active. However, it is quite risky. There are three variations.

Most importantly, look out for the d5 square. It is the "main square" of the Italian

Sub 1800 players play the steinitz(d6) nearly half the time against me. They seem to be worried about that pawn. It seems that club players should spend as much time studying that as they would the main line because I see it all the time. It's more common than the Berlin at club level. 

THe OP asked how to play Ruy Lopez with black...

Moreover, some of your variations are wrong, bad move order, etc...