These are very good questions. Unfortunately the answers are impossible to know. Bearing that in mind, I think Houli has every chance of having a great season without quite setting the DT world on fire exactly and Jetta may well play 22 games (or close to it) if he stays fit and may have a good output especially relative to his price.
By good, do you think he will score around the same or higher than the Tomahawk? He is my cheapest foward and am hoping for high 60's low 70s out of him before i upgrade. However if Jetta can score around the same mark it will save me 50K which i can use to improve some other areas.