Finish advice.

I got a Lanakai tenor as a gift for my nephew.
http://elderly.com/new_instruments/items/LU22E40.htm

Before I give it to him, I need to address some finish issues.
The matte finish is quite rough and there are some spots on the sides that are almost rough enough to give splinters.

I work with wood daily so I have a full array of sanding supplies from 80 grit all the way up to 1200 in sheets and 2" disks.

My finish of choice for my wood art is heat treated walnut oil. It hardens nicely and is food safe (irrelevant for ukes).

Can I get away with light hand sanding with oil touchup?
What grits should I start and finish with?

Or what else would you suggest?

Thanks in advance.

True oil is a popular finish. Needs a bit of cure time. You say matte finish- any idea what type of finish product is on there? That will onfluence your choices.

I don't know what Lanikai uses, but there is not much finish on there at all.
I believe the oil would soak into the wood in a lot of places, which leads me to maybe sanding all the body and starting over, so to speak.

i'm surprised Elderly would sell an new instrument with such a bad finish. At that price point, a rough finish that causes splinters is unacceptable. Have you thought about returning it? If you need to fix it and can not return it... Tru Oil is a good choice. Light sanding, maybe a wash coat of shellac and then several light applications of Tru Oil – 000 steel between coats.

I probably broke rules 17 through 39 in the luthier's guide to finishing, but here is what I did:
Gently hand sanded the rough spots with 800 grit.
Wiped on just a bit of wanut oil then buffed the entire instrument with a lambswool pad mounted on my close quarter drill.
There was probably a bit of walnut oil/beeswax residue on the pad, so I'm guessing some of that stayed on the instrument.
It's still has a slightly rougher than normal feel, but it is much better than it was.
I am guessing time and use will give it an interesting patina.

The "rule" in this case is "fat over lean", and that's what you did. I'd go with either the TruOil or Waterlox, though. They'll "dry" (actually polymerize through bonding with oxygen) faster than walnut oil.