You do have some decisions to make. I respect the opinions of the posters here; I've learned a lot from these and other posts, even though I've been touring off and on for 30 years. I think this is the best place for advice on bike touring. My experience has been that folks in local bike shops have little or no experience with touring.

The quest for finding the perfect bike with the perfect components, perfect setup, and perfect equipment to strap on may be a lifelong struggle with no end. For me it seems to be. That's okay; I think it's fun, and I've already arrived at a really good setup that makes touring a joy. I'm chomping at the bit for summer for my next tour!

Here are some thoughts to add to the pile:

Mechanical breakdowns are a drag. I guess they're inevitable, because no matter what I do, I still get the occasional problem. Good equipment choices and proper preparation minimize problems so I haven't had anything major happen for several years. Keeping your load light also helps a lot. But still, it's good to know how to fix problems, from adjusting brakes and derailleurs to replacing spokes and truing a wheel. I approve your choice to travel light (something I'm not good at) and encourage you to fill in any gaps in your bike mechanic skills before you leave - just in case.

You can tour successfully on just about anything. Based on the quality of your choices, I'd say the bike you ultimately choose will be successful. Agonize as much as you want about it, then try to avoid regrets that you may have made the wrong decision.

Will the bike you buy become your regular ride after the tour is over? If so, that might be a consideration. Which bike would be most satisfactory as an everyday ride? In my case, I wanted a bike specifically for fully-loaded touring, so I bought an LHT, and I'm very happy with my choice. It's an okay everyday ride, but a little heavy, so I bought another bike to be my everyday-er. The LHT can rest between tours.

Enjoy! You're going to have the adventure of a lifetime!