Hello !
I wanted to know if a stealthier character that uses sneak is at all viable
Some other people may answer better than me, but Sneak might change in the sooner future, because it was quite upside down recently. You might make a Sneak character and then discover that it has been nerfed. I suggest you to choose another build, waiting for the change to occur.
If it isn't what is a good build for a beginner.
Are you a loner or do you have a faction ? If you are a loner, I highly recommend you to use Small Guns. Besides, you'll need Outdoorsman, and maybe some First Aid/Doctor or a bit of Barter. If you have a faction, it depends on what they can provide you - if they have big guns you can use big guns, even if I don't recommens those weapons for beginners.
Also are throwing knifes any good as a weapon.
Yes, but they are hard to get if you are playing alone, I think. Also, I think they are useful in PvE but really less in PvP.