Not Jwelch, but we have done all of these in the past
With mixology, every time we have done it, there has always been at least some of it where you make a drink yourself. Sometimes, they had a table or bar area set up where people participated in making drinks. Sometimes, they have preparations at each seat for everyone such as mixers, cut fruit, and muddlers.
Stem to Stern was a one and done for us as we did not find the wines interesting, but this varies from cruise to cruise so you may have a different experience.
Rum tasting will be a selection of rums that are good for mixing and rums that are good for sipping. There will be comparisons of the various types such as light, gold, dark
Mojito is often with caipirinha and is one of our favorites as it is often offered at one of the bars on
Castaway Cay. You try different rums and cachacas and get to make muddled drinks.
This is a list of what they have offered in the past -
https://disneycruise.disney.go.com/onboard-activities/beverage-seminars-tastings/