Tipping at Hotel Xcaret México — what's customary (and what's not)

Gratuities are technically included, but tipping for great service is common and appreciated. Rough ranges people actually use: housekeeping $1–5/day, bar $1–2 a drink (or a $5–10 tab if you're parked at the swim-up all afternoon), butler $20–100 for the week depending on how well they did. It's optional and never expected. What do you tip, and for whom?