Since you did not mention that you had elite status with either dl or aa I am guessing that you will only earn base miles and no bonus miles based on status.

Unless you are doing this trip in conjunction with other trips either previously taken or that you are going to take later in this year in order to earn status than I would go with the wn code share flights with ata. Especially if you can get a stopover in phx with it. The amount of miles that you could earn with either dl or aa for what amounts to a significantly higher priced ticket are about equal to what they would cost if you just went and bought the miles without flying.

If you do have status or are planning on earning it this year with aa or dl this year than purchase a koa-phx tix that will encompass the workshop in phx and purchase another tix from phx-slc.

A suggested itinerary:
koa-hnl-dfw-phx-dfw-lax-koa = 9760 aa miles + bonuses (?)
phx-slc-phx = 1014 dl miles + bonuses (?)

total cost for close to 11k miles = $950 or $250 more than what you would pay for not earning any miles. For $250 you could buy the miles directly from the airlines.

I would only do the mileage earning trip if I needed it for status or if I already had status and was earning another 11k status miles. YMMV