Theorycrafting a Monk (Invoker) pure caster build

So, I'm going to start a co-op playthrough with my middle school-aged son, and he wants to play a wizard -- a male spellcaster; seems like the monk is the best option. So I need to come up with at least the outlines of a monk caster build for him (given how difficult respeccing is), since I haven't seen anyone else do one. I have some core ideas, but could use suggestions on how to fill out the build.

The core idea I have is to combine the Threaded Light Woven Focus (which basically gives you as much %increased spell damage as you have spirit) with the Lead Me Through Grace ascendancy node (which gives spirit based on evasion/es on chest, but then says you can't get spirit anywhere else), which you want anyway since it is on the way to the best defensive ascendancy node. This would put the character into the great position where the same thing scales both offense and defense (evasion/es on chest). It might be the best way to build around Threaded Light, I think, since you won't need to use a sceptre to boost spirit and so can use a much better spell-damage oriented wand.

Defenses: the standard Monk package. Get enough Dex to use Evasion/ES hybrid gear and put the rest in Int. Get evasion and ES as high as possible, turn evasion into armour with the Invoker node (And Protect Me From Harm), use Grim Feast/Wind Dancer/Arctic Armour/Ghost Dance/Blasphemy (Enfeeble). Blink if enough spirit.

The two questions I have are: (1) what should the build do for offense, and (2) what should the tree look like.

Regarding offense: the nice thing about Threaded Light is that it gives generic % spell damage, and wands also seem to roll % spell damage and +level of spell skills, so this build should be able to use just about any spell or combination of spells. I have been running a Warrior minion build, so I don't know anything about spells. What spells or spell combinations would be good fits, do you think? Could drop some defensive auras to run a "Cast On X" meta gem (which would fit with Invoker), but I don't know if those are worth using or building around post-nerf. Any suggestions? I really have no idea what direction to go in here.