T5 lamp wattage is much lower than T12 wattage. You can expect roughly 111 lumens per watt from a new 14w t5 lamp. So your 14 watt lamps will produce roughly 1554 lumens each. They will be perfect for your tank.
I knew someone would know the math for it and could verify whether these would be fine. Thanks, Oregon!
Octopus,
Seeing your setup, your lights are definitely going to be fine. It is different seeing that your lights are over the growing space shelf and that the plants will be right in direct contact with the best light. So I am pretty confident it will go rather well. You can always go bigger, but like I keep saying in my other posts, I think your plants are going to grow well and be very happy. Once you start growing on the edges of your tank there on the sides and front, you might benefit from getting longer lights or more of the same lights to cover those spots. 4-foot shoplights with T12 fluorescent bulbs are cheap.
Getting the mirrors around the back and sides and I even suggest the bottom will help make use of your light. But your tank is a unique shape, might have to settle on reflective foam or tin foil to cover it more easily. But if you are up to it, and if I were you, I would get the mirrors up all around where you don't want to look in on your plants. Save some viewing space for sure.
VFTs:
Flytraps are just more robust in sunlight. I don't mean to make it sound like you can't grow them there. You will, and they will just need the attention to help them go into dormancy next winter and you will have some neat VFTs growing in your space. They just are EVEN BETTER in Sunlight, not that they are going to die in tanks.
Temperature:
Your garage temps are pretty low at night. Temperate plants coming out of dormancy might appreciate it and do really well, but any plants that don't like 50s at night are going to have a rough time. Do you have a list of the exact types of "VFTs, pitcher plants, sundews, butterworts, etc." you are going to have in there? Many of those will be fine with the temp drops right now and as it goes throughout the year. But some tropical sundews will not like it, you might have to wait for warmer temps for those to be added. Just depends on what you plan on growing.
You only need a heat source if you plan on growing anything that wouldn't like the 50 degrees nights. VFTs coming out of dormancy and some temperate pings will do fine.
"Spraying it down daily"
Because it is your garage that doesn't have a furnace heating the space and drying up the air and that you live in San Francisco already naturally humid, I wouldn't spray your tank. In fact, I wouldn't even cover those holes you have up front until you check the temps and humidity.
Looks like your setup is there and ready to start testing, so if you have a hygrometer already, place it in the tank on the wood plank with the lights on their schedule and see how the temps and humidity handles for a day. See what the highs and lows were and then decide if you even NEED to spray or close those holes off.
If you don't have one, I can recommend this cheap and works good enough for me Hygrometer you can buy from a from Home Depot:
http://www.homedepot.com/p/AcuRite-Digital-Humidity-and-Temperature-Comfort-Monitor-00619HDCSA2/202260980
Looking good, Octopus! I am excited to see you fill that with plants!