Wow you jumped on those boxes fast… they look cool. Very curious to see how they work for you.
I’d say don’t worry about killing everything in the hulls or soil mix. Work on getting everything to work in harmony. If there is a explosion of a certain type of critter, then perhaps see how you can keep them in check… If you’re gonna go organics, I’d think you’d need the life in the soil to help keep everything in balance.
You can definitely use teas, and top dressing is recommended in those boxes. Only use teas from the top though, and not down the tube, and only use sparingly. The Build-A-Soil on YouTube videos break down their use pretty well, look for their video series in the 10x10. He’s comparing Earthboxes (similar to what Badger got), 10 gallon smart pots and a 3 x 3 no-till bed. Will be interesting to see the final results.