I think that "Na realidade" it's not a natural thing to say, even it not being wrong. The most usual would be "Na verdade".
could you say um homem bom?
when can you put adjectives before and when do they have to go after?
homem is more formal, while rapaz (guy) is informal. about adjectives, try this link http://www.duolingo.com/comment/291992
Is "good guy" an acceptable translation for the subject of the Johnny Alf song "Rapaz de Bem"?
Is this wrong: "Na realidade ele é um rapaz legal."
One of the translations given for "guy" is "tipo". Would it be correct to say "Na realidade, ele é um bom tipo"?
I think I've never used that in my life and never seen in my region either...
Tipo (meaning guy) is portuguese from Portugal. So you can use it there. hehe
I'd imagine it being acceptable. While I haven't tried it, the way "tipo" is used in PT-PT exists in other European languages as well.
Han är en bra typ (Swedish)
Hän on hyvä tyyppi (Finnish)