I think the Jags would have to fire Mularkey and bring in someone more defensive minded if they want there to be any chance of this working out well. Tebow needs a head coach that is a defense first guy who hands control of the offense over to his OC and who is not held responsible for Tebow's failures. You're very unlikely to find a good Head Coaching candidate willing to accept blame for Tebow failures. I don't think McCoy would take the job and I don't even think McDaniels would go there again. Both currently run offenses led by Manning and Brady they can afford to wait for a better opportunity if there isn't one already available for them this year. However with a defensive minded head coach you can hire him to build a defense with assurances that he won't be blamed for offensive failures. You also don't have to worry about him forcing his offensive system on Tebow. You then hire a college OC who runs a similar system to Florida's and an NFL QB's coach to work on improving his passing.
With that said this is a lot to ask and I don't think the Jags would go this route nor am I suggesting they really should. However if Khan wants Tebow he has to go all in. None of this he'll be given a shot in camp stuff cause we know that just won't fall in Tebow's favor and suddenly you've made the same mistake the Jet's did (having a backup QB that is merely a distraction). The only chance Tebow has of success in the NFL is going to an organization that is fully committed to him and his style of play. Ultimately though the chances of success are still minimal without marked improvement from Tebow. With that in mind if I'm the Jags I pass and let him pursue other opportunities (CFL) and try to draft a QB that will make fans forget about Tebow.