Need some help on two bikes.

1. I have a bike that I bought from Bike's Direct (Save up to 60% off new Hybrid Bicycles | Adventure Hybrid 29er Bikes Elite Adventure Sport Trail). I like the bike but the suspension fork sucks. I would like to replace it with a rigid fork. However I have no idea where to start or if it's even worth doing. How would I go about finding the exact size of fork I would need?

2. My Fuji Absolute 1.7 is what I ride all the time. There's nothing with it. For aesthetic reasons, I want to get a flatbar to replace the riser bar I currently have. I see relatively cheap carbon fiber flat bars on ebay and amazon. Are they any good or should I stick with aluminum?

Thanks for your help!