I'd imagine by Oct 2022 that we should be back to some sort of normalcy in terms of cruising. I hope fish extenders are back by then. In reality its all speculation until Disney decides if they're keeping the rule they have for the UK staycations for all US sailings as well. Time will tell.
Same with other activities on the boat. The Oct 2019 navigator is a great place to start, I also highly recommend looking on YouTube for Vlogs, usually you can type your ship and HOTHS or Halloween and I bet you'll find some! They go through day to day showing the different things available. Obviously things can change by Oct 2022 but it'll give you an idea