I need some clarification on the Attune Item Metamagic. Does the weapon count as magical for avoiding Immunity to Normal Weapons? It recently came up in a game and my first instinct was to allow it, since it was a mystic ritual and you spend Karma on it. Opinions please.

No. The adept effectively has a supernatural affinity for this one item, increasing his limits on tests.

Are your players trying to get around the restriction that ranged weapons cannot be foci (or at least not effectively so at a significant range)? If the adept just wants a magic sword, a weapon focus may be what he is looking for.

He wanted to know if he had to turn his sword into a weapon focus.

Sadly, IIRC, You cannot actually Attune to a Focus... so it is one or the other. No stacking.
Atr least that is what I remember - Away from books currently.

Yes, but a focus can be imbued with the the Alliance trait, which does the same thing as Attunement. See, Imbue Item, Street Grimoire pages 132 and 133.

What about Imbued Items? Would they work to bypass Immunity to Normal Weapons.

No. An attuned item that is also imbued with the single allowed feature (even one as, IMO, trash as Alliance) is still not magical.

Otherwise it's a focus, likely a weapon focus and that is already enough to bypass ITNW.