Final CR determines WBL (check Bestiary for which category a hag falls under - it's probably a Combat critter, so witch levels probably add half to CR).
I would say adding 6 class levels to a creature would be the same as adding 6 class levels to a classed NPC in terms of CR, making it a CR 10/11 (since it was a CR 5, and depending on whether or not you think you should add the full class level or class levels -1).
Figuring out CR is really more of an art then a science.
As for how much wealth to give it...
In theory the hag (which has no items) was rated a CR 5 based on all it's inherent abilities.
I think that probably you should give it the wealth of a creature that is level 10/11 minus the wealth of a creature of level 5.
So...
62,000gp - 10,500 = 51,500 gp.
Hags have standard treasure, which is replaced by gear for its total CR is my suggestion. In the end you'll need to compare it to the final CR baselines to figure out where everything winds up. :)
If it's an NPC, I'd give it Heroic NPC wealth by level for an 11th level NPC, which would be 16,350 gold. That lines up about with 6th level witch PC wealth.
Hags have standard treasure, which is replaced by gear for its total CR is my suggestion. In the end you'll need to compare it to the final CR baselines to figure out where everything winds up. :)
CR of monster doesn't incorporate outfitting them with gear from their treasure though.
I know it's something some GMs do to make monsters more challenging, and I think it's smart, but the CR number for the creature is based on the stat block as written.
Harley Quinn, you do have a fair point about NPC wealth by level vs PC wealth by level. Theoretically, switching from NPC to PC wealth by level is an effective increase to CR by 1.
A monster with class levels always possesses treasure equal to an NPC of a level equal to the monster’s final CR.
To determine the value of this gear, use the value listed for a heroic NPC of that level.
Determining the final CR for a creature with class levels requires careful consideration.
While adding a class level to a monster that stacks with its existing abilities and role generally adds 1 to its CR for each level taken, adding classes that do not stack is more complicated.
Table 2–4 gives general guidelines regarding which core classes add directly to a monster’s abilities based on its role.
Classes that are marked “key” generally add 1 to a creature’s CR for each level added.
Classes marked with a “—” increase a creature’s CR by 1 for every 2 class levels added until the number of levels added are equal to (or exceed) the creature’s original CR, at which point they are treated as “key” levels (adding 1 to the creature’s CR for each level added).
Creatures that fall into multiple roles treat a class as key if either of its roles treat the class as key.
So, because a green hag is considered a Combat role monster, adding 6 witch levels to it would increase its CR by 4(the first four levels add 2 to CR and the last two add 2) raising it to 9.
The hag would be treated as a 9th lv. heroic NPC for treasure and have 10,050gpEDIT :
oh, didn't see that you wanted to give the hag PC money.
In that case it would have 46,000gp and its CR would raise by 1 to 10