There are two things going on here. One, if you use lights to heat anything, you will want a proportional over an analog thermostat. This is because the analog will turn the light on and off as it is controlling the heat vs the proportional just reducing the power and producing a dimming effect.

Second, though you can use one thermostat to control 2 or 3 different items, they must be of the same wattage; you can't plug a 1ft strip of 3" Flex watt and a 1ft strip of 11" flexwatt into the same thermostat and expect them to maintain the same temperature. Since they use different wattages per foot, they will heat differently

This said, as long as all the heating items you want to use are the same wattage, you'll be fine. If not and you have the cash, go for the Herpstat II or the Herpstat Pro. Both of these have separate temp senors so you can use them on different cages/wattages.