My recipe calls for Fluid flex liquid, I could not find the high ratio liquid but, I found CK high ratio solid. How do I incorporate the solid in a two step method cake? 

http://www.foodservicedirect.com/product.cfm/p/180728/Nutex-Hi-Ratio-Cake-Liquid-Shortening.htm

two totally different beasts.   
Not interchangeable.

Can I use the high ratio solid for buttercream icing? 

Yes.  You can actually use less high ratio shortening than you would butter or reg shortening. Charlottes whipped cream bc is a prime example of this.

alpine is icing shortening only.

sweetex is baking and icing.

ck says they are both but I dunno.

cooks cake and candy actually sells small amounts of the fluid flex/nutex. Can't remember which.....

Thank you for your time and input!