No problem, that’s what the forums are here for. Just try searching as well because there is a lot of stuff that has been answered in the past.
1. Tattoos don’t give negative stats. They’re all good! 😀 If you found one that gives negative stats please report it.
2. Only on retail, private L2OFF C3 didn’t support Dyes (only C4+)
3. No but it’s a nice idea. At the moment we have a C3 Skilldex: l2oldskool.org/skills , but we should definitely have the same for NPCs and Items. I’ll add it to my todo list.