I worked on one cat gasoline splitter which had a fired reboiler. The boiling point range was quite narrow so controlling the outlet temperature as a way of how much heat was added wasn't practical (especially when you looked at the phase envelope with pressure changes).
The solution was that the reboiler was a pumped design. Firing was cascaded off a tray in the bottom section of the tower as a control point but essentially, the pump around flow was large enough you couldn't fire hard enough to go dry in the furnace. They did have high temperature trips on the pass outlets but with the composition changes and pressure effects, I don't think they could be relied on to ensure you weren't going dry.
Basically, you need to look at your system and come up with a control system to keep you from going dry if that's your concern. Since the latent heat is much more constant, you can have some sort of a firing limit based on the feed flow rate to ensure you don't go dry.
As 25362 pointed out, feed preheat is usually done by exchanging with some of your hot products but it really depends what you are going to do with those products. You definitely want to cool those products if they are going to storage and therefore that heat is available to preheat other streams but if they are going to another processing unit, cooling them down may not make sense but then again, it might. There's not sufficient information to really advise you here.
If this is something you are responsible for and not an engineering assignment, you really should consider hiring a consultant company. I don't mean to be harsh but you seem to be way out of your depth on trying to make these level of decisions.