Very good! The pair togheter looks very nice. I don't remember to have problems with mirror skin weights. It's just decide the correct plane of simetry and check or not the box for x mirror. Before...

You're doing good. I like the eyes very much!

About smoothing the model: Why don't you try using smoth proxy mode? You stay with your low poly model, but is able to see how it looks softened. Pressing Pagedown and PageUp you can see your model...

Your chars have a really cool apearence. I like cute characters very much, but it seems I'm not able to model that. Everything I do goes to the realism side, and sometimes this gets me annoyed. But...