So - you don't want to line wool with another fiber. Fleece requires regular washing and wool doesn't. If you felt your wool really well before sewing, you could get away with it just fine. It's not going to hurt anything. but then you're kinda defeating the purpose of using wool entirely.
As for the blended fiber, it would probably work, but again, it's not wool, and it's going to require more regular washing. What you don't want is a blend of animal fibers with vegetable fibers (cotton, rayon, linen), but a blend of animal and synthetics will do the job.
I totally second the suggestion of Kozy Wool. We used them almost exclusively until DS was about a year. Small and Med was plenty for us (although the Sm took some growing into). Look for co-ops on it, it's a lot cheaper. We also got a bunch of custom longies made, since DS is so tall, with extra long legs. It is a long lead time, since they're all made to order, but they work great. The problem I ran into was relanolizing them (which I suck at). So mostly I just used them until they started getting soaked, and then retired them. I have a pile of them I now need to figure out how to lanolize for this little bean.
THey didn't work for night-time though. For night-time we still use Babyology. And at 2 with a super thick night-time dipe he can still wear the Mediums. The Large is way too saggy in the crotch.
I did knit a few for the NB period - I like the patterns by Little Turtle Knits with the ribbed crotch. The big thing for wool for me, is it has to have a drawstring. Most do not have the resiliency to be able to pull on over a dipe and then stay up. They stretch out the first time you wear them, and then don't spring back until they get washed again, so a drawstring is crucial. Babyology is the only brand I haven't had this issue with.
If you want wool wraps, I highly recommend Pipers Closet. You can find her on etsy, I think. If you can't find her, LMK, and I'll look up her info. I hope she's still in business. I love her wool wraps. She'll do a custom size (we needed a Med waist with a Lg rise), and it was in my mailbox in less than a week. Great prices too. I wasn't as crazy about her dipes, just because they have internal soakers, so they take too long to dry, but the fit was excellent. We have a 2 layer wool flannel and it's a great night-time cover. I've also used her thinner ones (they're still 2 layer, I think, but a thinner wool), and they're great day-time weight.
Washing - pain in the butt. This is where you really need to be sure your dipe is fitting properly, because hand-washing the poopy out of the wool is a BIG pain. And they don't dry quickly. Although if you take a towel, fold it in half, lay the wool on it, roll it up, and walk on the roll, the towel will suck all the water out of the wool. Then it'll dry overnight most of the time. But if you skip that step it could take a week to dry. I'm actually at the point where my washing machine has a "wool" setting, and I'm willing to toss everything into the machine with Charlie's Soap, cross my fingers and go with it. I just don't have the patience for handwashing all the wool anymore.
And then there's lanolizing. Which I suck at. So if anyone has any brilliant suggestions, I'm open to them. I do have spray-on liquid lanolin, which I should probably just go ahead and use. It's better than nothing, I suppose. Another thing about lanolizing is that you really want a dedicated vessel for it (bucket, tub, etc.). The lanolin sticks to the container, and then it requires several scrubbings with soap and hot water to get off. And any that you pour down the drain will need to be chased with boiling water or it'll clog your drain in time. I really dislike working with "solid" lanolin. Even liquid is a pain, but solid is so much worse.