It's probably possible to make replacement hands that are strictly better, but the thing with handlikes is that there's a fairly long learning curve for anything that complicated, and nobody wants to go without dexterous hands for possibly up to a year or two (though most people do have the second set working well enough to get by with within a couple seasons), and if you're going to be adding extra arms for the new set anyway there's not much incentive to do the design work for something that's strictly better rather than just differently useful. This mass of tentacles comes closest; it's a bit prone to dropping things in moments of inattention but has better grip strength and dexterity and the ability to do some tasks one-handed that usually require two hands and/or a specialized tool. The greebles on the other hand are mostly strict improvements; she personally likes the wrist tentacles best (hers are hard to spot against her fur when they're wrapped around her wrists) and the extra thumbs are also popular.
The wings are quite large batlike affairs, but jointed in a way that lets them fold down small enough to fit through most doorways without much fuss; chairs are more of a problem with them, and he'd most likely want to add a few of those reinforced loops to help keep clothing on around the side flaps. They allow for gliding about twice as far as the height you're starting from, and triple or quadruple the height it's safe to jump from depending on skill; jumping out of a flying machine or something is still inadvisable without a parachute, and most people prefer to stick to hang gliders if they're going to need equipment anyway.
If he wants a dick there's a couple related choices he should make - the easy one is just whether he wants to be fertile that way or not, which is an entirely stand-alone choice. (This won't make him interfertile with crafters if he's not already, which she has no idea about.) The other one is what he wants to do for hormones - those affect things like hair growth and fat distribution and what people smell like, all those subtle differences between the default sexes. Crafters mostly do fine on mixed hormone systems but most other species tend to have problems in the long run that way, so it'd be risky for him to try it, and if he switches over to a male hormonal system he won't be able to bear children, just sire them. It's also possible to make it male-typical amounts of obvious that he's capable of bearing children even if he wants to keep the ability to, though that means he'll require crafter assistance to give birth - any adult crafter can do that much fleshcrafting, so it's not a huge limitation, but it is pretty risky if he's not sure he'll be able to get to someone in time.
She can totally make him a bigger swatch of one or two of those furs just to have, by the way.