So you just put the mylar bag of goodies down in the hole with sand and debris?
You might want to do some small engraving on the new stone directly above the hole, in order to at least give future owners the opportunity to notice that there is something underneath that is worth looking for... before they have it demolished.
Not tobacco. I'd end up remembering that I had 10 year old aged tobacco that may not even be in production anymore. No way I wouldn't end up digging it up.
