Wool: I like wool for fashion, but for outdoors, especially a bike trip, I'm sold on synthetic fleece. Can be washed easily and dries relatively fast. Tough. Still warm when wet. Available in different weights. Then a shell over that. Fleece these days can be had fairly cheap.

Tent: REI when on sale are usually good deals. My preference is a 2-person rectangular dome tent, with just two crossing poles, (I don't like systems with the extra complexity and special parts of pole hubs), and a cover fly with a short pole that provides an overhang over the front and back windows. This tent has excellent ventilation due to that. At one point I bought a similar tent with full coverage fly down to the ground in all directions, with front and back doors and covered vestibules at each, but the problem was, that tent had no ventilation in hot weather. And, the vestibule was not big enough to keep the bike in it.

Besides the bike and specific accessories, I'm not seeing many thousands of dollars in other gear, unless you're going top-line and paying list price.

Panniers, buy the best you can, because if they break, you're outta luck. Ortlieb looks good, have a good warranty I believe, and a large network of dealers to honor it. They sell cheap copies on amazon, but on a long tour, I'd get a name brand. Jandd used to make some expedition quality ones, tough, but not waterproof and these days I would want that, and they don't make their panniers any more. Even with quality, one long tourer recommends straps to support the pannier weight and not rely on the modern plastic clip setup, and also horizontal straps instead of the inside lower clips or springs.

Racks also, should be first-rate.