Gameinfo.txt is what determines where assets are located. Your gameinfo is omitting tf_dev by design. see the problem?
The potential solution is to make compilepal load tf_dev's config instead but that one comes with its own set of problems and hurdles that I cannot help you with. When doing so, people have reported that the game client cannot be launched, which makes sense since tf_dev is not really a valid source game. For CompilePal, that means no more automated cubemaps and nav files.
So yeah, either way, there's things that are not going to work.
-The tf config is incomplete because it doesn't know where your assets are
-The tf_dev config cannot launch the game since it's not really a game folder.
So yeah, bottom line, I cannot advocate for tophatwaffle's "custom content without contamination" approach because it obfuscates things intentionally and creates two different game configs that are both dysfunctional on some levels. Anyone using this setup should fully expect it to mess with their workflow at some point. It's a pretty creative workaround to keep things separated in csgo but in the case of tf2, we're fortunate enough to have the custom/ folder which more or less negates the need for this twisted setup.