For such a tiny budget, you seem to be agonising a lot. IMHO, if you care at all about this, you should be going to a bike shop, and getting their advice, and going with that. Such a cheap bike is going to need work relatively soon, so you're going to spend time at a LBS sooner or later. With the Zeller's thing, you can't even see what components it has. It's um, telling that "steel frame" and "handlebar brake" are listed as features. You would get much more bike for your money on eBay or craigslist.
Don't forget you're going to need to buy the basket ($25 ish) and lock ($25-50) and probably lights ($30-50).
So, um, agonising over which crappy department store bike to buy with your $100 doesn't make a huge amount of sense to me - or asking the "experts" here to help you pick.
Steve