Well, first important thing you need to reconsider is your wood choices. Since you're choosing a set-neck model, your body/top woods are going to have more impact on your tone than they wouldd in a through-neck bass. If you go with the ash body, I think that means less deep bass and more midrange. Your cocobolo top would be really helpful on this bass. The most Alembic sounding wood combination will probably be cocobolo over mahogany or vermillion. Moving to the Essence model will probably cost you about a $400 upgrade charge to get the through neck, and then it won't matter quite so much.
This all comes back to your priorities. The key factors seem to be price, feel, tone, and appearance, in whatever order they matter to you. Then you have to consider that these are all subjective concepts, so my preferences won't necessarily match yours. I think you know what yo uwant the bass to look like and what you want to pay. I don't think you have represented as well your preference for feel or tone. You seem to be a Dead fan, so I would think the more traditional Alembic tone would please you more than a Fender Jazz. While an Alembic in ash wouldn't sound like a Fender, it would be more in that direction than I would want to go for myself.
With regard to scale length and body size, I doubt the Tribute body is any smaller than a small standard body, and it's probably a bit larger. It's certainly thicker. You may be able to use the regular Tribute body size with a medium scale bass neck, especially in four string with Jazz-bass spacing. They could tell you better, but I think that might balance out pretty well.
Who knows, maybe I am nuts. Thin kabout all this stuff, validate what seems important to you, and make your own decisions. It's your money and it will be your instrument. Best of luck!
