Some interesting ones there and sounds like you have a similar philosophy to me - don't customize to the point that context-switching to bash is a pain.

For tab-completion I actually prefer the builtin zsh completer set to use the menu mode - this is one of the big improvements you get with zsh over bash / etc to my mind. I have in .zshrc

  zstyle ':completion:*' menu select=2 select=long interactive

You can set it to use your ls colors with something like

  zstyle ':completion:*' list-colors ${(s.:.)LS_COLORS}"