We're barely scratching the surface of our technological potential, not just medium or long term but especially short term. The politicoeconomics are what's stopping us from going to Mars now. Look at Elon Musk. One of these humans is enough to show how feasible a short term path to Mars is here and now. Imagine if there were a hundred Musks going at it. There are others (Bigelow, Carmack, Greason, etc), but he's probably the best example for the purpose of the conversation. Rockets and spaceships fit for NASA's needs, at a fraction of established prices. And he's a believer.
Next you have all the accessory technologies. Medical, materials, energy, etc. We have been making progress. Just not as directly and explicitly as we could've been.
Muscle Monster Aliens could walk around there, otherwise life maybe only in Water? If Kepler-22b's radius is really 2.4 times that of Earth,
we could not walk one step there.
Probably not.. 8 times Earth mass is assuming same density.. But even in most optimistic/favorable difference of density, it's probably no walk in the park for humans. Would be real interesting to see what native life looked like though. Maybe they couldnt survive Earth gravity natively either.