Also, were you 100% sure you actually put them in your suitcase vs put somewhere safe to be packed later?

Did you take a flight and leave your case unlocked? It's more common for things to be taken at the airport. If your suitcase was unlocked, theft could have happened anywhere along your journey.

A hotel housekeeping job is decent wages for those who have to take the job. Most would not jeopardize it for a small amt of souvenirs.