Do I hold the ukulele differently when I'm fingerpicking than when I'm strumming?
No. And, often you'll have to go quickly back and forth between fingerpicking and strumming, to achieve the musical effect you want. So learn to hold it in a way that is comfortable for both.
How many of my fingers can I use to finger pick the ukulele?
You can use all of them. I occasionally use a pinky here and there, but it's not often - most folks have more fingers (including the thumb) than most ukuleles have strings! There is no finger you're not allowed to use.
My picking-hand pinky wants to anchor itself on the front of the ukulele - is that okay?
It has it's upsides and it's downsides. It makes moving to a strum more difficult. I developed the habit playing steel guitar, and it doesn't mess me up much on the uke. I had a classical guitar teacher when I was a kid who really hated when I did it. But I'd say, if it helps you, it's probably okay now and again.
Can I do as much fingerpicking a uke as I could with a guitar?
No. A guitar has lots of strings on which you can play bass notes - much more complicated arrangements are possible. However, you can do quite entertaining pieces on your uke if you can finger-pick well.
Will learning to fingerpick a ukulele help me learn on other instruments?
Absolutely! Your fingers will know all the basics already - how to find the string, pluck the string, stay away from the string after it has been plucked, how to find another string, etc.
Why is it so difficult?
It just is. Each finger has a really complicated, fine-coordination task to do, quick, in time, quickly quickly quickly. But if you follow the basic lessons and drills in this series, and drill the ones you find challenging a little bit each day, two of your fingers will learn the basics very soon, and it won't seem so difficult at all!