B737 Captain reported multiple system failures during pre-flight at the gate. Crew notified maintenance and refused the aircraft.

Narrative

Aircraft X was about two hours delayed on the inbound and we arrived while boarding was already underway. During preflight the first officer commented that the air temp gauge; which is the only gauge we have for effectively the entire operation of the air conditioning system; was not working. As we began to look into this; the needle was pegged at 0 for nearly all indications of all supply ducts; zone temps and both packs. They were both supplying air; so they were not frozen; and the aircraft was uncomfortably hot; so the readings were clearly inaccurate. We contacted maintenance who deferred both the pack temperature and supply duct functions of the gauge per MEL. While we were not thrilled at the prospect of having little to no information about the air conditioning system; we discussed with the FAs the need for more communication than normal regarding the cabin temperature and completed our preflight duties.As we were running the before push checklist I observed a dim LOW PRESSURE light on the number 2 forward boost pump. Because it was dim I had not seen it before in the bright flight deck. This also caught our attention as the same pump had been written up the day before by another crew and ops checked good. I attempted to cycle the pump without success. Maintenance was contacted and the jetbridge reattached.We agreed to defer the fuel pump per MEL and the crew; Maintenance Control and dispatch was on board with this plan. As we were working with maintenance to pull the required circuit breaker per MEL; we observed a number 1 forward boost pump LOW PRESSURE light. Maintenance also saw this illumination. After multiple cycles of both the switch and electronic equipment bay circuit breaker; the light extinguished. Shortly after; the exact same thing happened with the number 1 aft boost pump. Again; it was eventually reset with both the switch and electronic equipment bay circuit breaker. Then we got a number 2 aft boost pump light. This last (4th) boost pump light is believed to have been from maintenance accidentally pulling the wrong circuit breaker; however the technicians insisted they had not touched either of the number 1 boost pump circuit breakers and had no idea why they illuminated. At this point the First Officer and I were concerned that the fuel system was not behaving properly or that something was happening with the maintenance procedures that was not expected. Either way; we had now seen all 4 of the main boost pump lights illuminate; 3 with no explanation; 1 deferred; within a few minutes.While all this was happening; the cabin temperature began to run away; which we had no idea about because of the first maintenance issue. By the time we found out about this; the aft cabin was hot enough that children were beginning to remove their clothes and the FAs were concerned for the wellbeing of a baby who was flushed and having a meltdown. I immediately made the decision to de-plane the passengers so we could re-evaluate our maintenance situation and come up with a plan. During the deplaning; both the FO and I observed a hydraulic system A quantity of 106%; not a big deal by itself but another maintenance item in what was becoming an increasingly long list.The FO and I called Maintenance Control and dispatch back to discuss our plans. We agreed to complete a full power reset on the aircraft while we discussed where our thoughts were. After re-establishing power; the air temp gauge continued to provide little useless information and we still had no explanation for multiple fuel pump issues. I decided that the cascading multiple issues to 2 of the aircraft's core systems with no reasonable explanation was an unacceptable risk and refused the aircraft. This was done; including the Electronic Log Book entry; on the phone with dispatch and Maintenance Control.The Chief Pilot Called shortly after to discuss the scenario and recovery plan. We ultimately were swapped into a different aircraft and completed thesegment approximately 8 hours late.