The thing that makes me chuckle about the fear of welding steel frames is the plethora of aftermarket steel fabrication involving bike frames that have been welded in various forms and configurations over the last century or so. Just Google homemade rickshaws, ice-cream vendor bikes, double or triple high clown bikes, side car bikes, home made cargo bikes and more recently ratrod bikes... jinkies! How'd they do it?
Personally I wouldn't care about steel or aluminum in itself (both are strong enough) but rather the build quality and wheelset. The drivetrain, as long as it works well and has low gearing, is good enough - as touring usually isn't high performance racing.
Flat bar vs drops is just personal preference.
Would I tour on a crappy bike? Probably not these days as I have some disposable income and enjoy wrenching on bikes, but I have. My first big tour was on a POS 1980s heavy gaspipe mtb with 2x5 gearing and stamped caliper brakes that only marginally worked. Still fond memories 32 years later.