Hi Ken -
From what you say it sounds like the 50 watt panel would be plenty to power the pump. Especially if you have batteries in the system. The load for the pump, 5-15 gpd, with no pressure and 5-10 ft of lift, is minimal. You could even consider running a pump directly off the solar panel and save yourself the expense of batteries and the inverter. A simple 12 VDC pump we carry is a possible match -
http://www.altestore.com/store/Solar-Water-Pumps/Surface-Solar-Pumps/Shurflo-Surface-Pumps/Shurflo-2088-443-144-12V-Std-Surface-Pump/p1088/By going this route, what we call a DC-direct system, you don't need as much equipment. No batteries, no inverter. If you go this route you can try the pump connected straight to the solar panel and see how it goes. If you aren't getting the performance you desire, you could then consider a pump control box, which would increase the productivity of the pump. And example of a control box it here -
http://www.altestore.com/store/Solar-Water-Pumps/Linear-Current-Boosters-For-Pumps/Solar-Converters-10A-1224V-Linear-Current-Boost-for-Solar-Pumps/p1354/ Keep in mind most control boxes are for direct systems only, ie, systems without batteries.
On the other hand, using a timer in a DC-direct system could be a little tricky as they normally require a battery to maintain settings and general functionality. Also, if you want to store some energy for other uses then going DC-direct is not the way to go. But you could still run that pump off a 12VDC battery and also use the same battery to power other 12 V loads. One thing to keep in mind is to have a small breaker box with breakers to protect your circuits.
The parts list you provided looks pretty complete except for all the breakers/fuses you'd need. I saw one fuse on there, but you'd want one for each DC load off the battery bank, including the inverter if you get one. Also one between the charge controller and the battery bank. Another thing you might consider is a surge protection device, which can help to protect your system in the event of a nearby lightning strike. Finally, how do you plan to mount the solar panel? It's important that you find a way to do so such that the tilt angle of the panel and the azimuth angle are optimal for best performance. You can see some of the pole mount brackets we sell here -
http://www.altestore.com/store/Solar-Panel-Mounts-Trackers/c459/You might look at the side of pole mount and top of pole mount brackets we have to offer.
As far as the particulars of the parts you chose, I can't comment too specifically because I don't know the model numbers of what you're talking about. Nor do I know if the battery bank you chose is sufficient given the items you wish to power, without knowing the power draw of each item and the length of time per day you wish to use that item. You can try one battery and see if that meets your needs and size up if necessary. Or you can get more sophisticated and use our load calculator to figure out how much storage you need -
http://www.altestore.com/howto/Calculators/c36/Good luck with your system!
Bramley