The reach difference is 10mm, very little IMHO. A seat moves that much.
Too bad they ran out of 56cm, but the deal is good so 58 should be sufficient. It's hard to find steel frames now and i like the simplicity of the bike. For instance it has 8 speeds and a Sora shifter, which spells durability over a 9 speed. Repair is big with me as i do my own.
Actually i understand and can agree with most points, best to throw a ton of money at a bike or even go with a custom if money no object. i am mostly trying to understand the stand over and it appears to not be too big of an issue.
if you have to compromise your seat position vis a vis the bottom bracket, you will be less than pleased with the handling outcome. if however you can keep your relative seat position, use a 1 cm shorter stem (but not shorter than 10 cm) you'll be ok.