@Ramadash - The 3 magics aren't too concerning to me if that's the playstyle you want to go with. Technically all can be used together and harmonize (magery for invis/heal/gate/walls/etc and weaving for gift of life/renewal/WoD and mystic for RC/sleep). Personal preference for me is to have mystic on garg so that you are always full speed (ie mounted) even when casting RC, but that does kind of limit some of the +skill items you can wear.
I'd agree with Drakelord though that I'm not sure why you'd want stealth (or hiding) on a PvM char (with magery). By having magery and mystic your friend can invis & mass sleep to break aggro on "dumb" monsters. There won't be any monster even close to a person that would reveal/fire field/poison field/para/wall you in/etc and none of them (besides a paragon) are very fast. Speaking of paragons, not sure how the char will be used, but those 2 skills are completely wasted if you want him to partake in the ToT events where paragons auto reveal. From my experience in PvM all you really need to do to get past monsters is pre-cast invis and just run full speed as far as you can.... if you get jammed up or stuck or hit with a poison then use your precasted invis and cure/heal yourself and then rinse & repeat. Having a spell trigger of mass sleep would make this even easier in case you really get in a pickle.
It depends on the direction you want to go here but you could easily swap those skills out for eval/med for a complete mage build; which allows for some additional damage to be done with magery (which can be huge when paired with a slayer vs any other magic) while a target is focused on a RC. Again this would be pretty clutch during a ToT event where you can equip a spellbook for whatever slayer. The 120 focus/med (paired with MR 4 legendary armor pieces) would make for an almost limitless pool of mana. Skills would be pretty straight forward and easy to macro.
120 - magery
120 - mystic
120 - focus
120 - spellweave
120 - eval
120 - meditation
If you really want to pursue the hiding stealth though, I'd opt for some stealth skill items (stealth leggings as Drakelord mentioned / stealth robe and cloak / jewels / etc) so that you can add more points to med.