I don't do SW so I cannot address your clowns and anemone. But for the rest , bag it. I bag and ship fish that have taken two days to arrive alive. When driving them you can overbag and do not need to add any air changed/adde along the way. In fact, you can leave the fish in unopened bags for over 24 hours. Just be sure there is at least 50% air in the bag and double bag them. Fixh in buckets can slam in a hard bucket wall. Bagged in a styro with some padding and they fare better.
Filer media need to be kept moist as does substrate. Plants can be wrapped in wet newspaper and bagged with an ounce or two of water.
Finally, this stand cill hold your 29 on top and 20L on the bottom. Titaneze makes dual tank stands that hold similar footprint stand over and under. a 29 and 20L are the same footprint. I did a quick search:
Walmart has it for $57.24.
https://www.walmart.com/ip/Caitec-Titaneze-20-29-Gallon-Tank-Stand/30500863