When you say you want to start a Templar unit do you mean a branch of us? Or, do you mean that you wish to do your own thing?
anyway I'm gonna ramble..
Dap is the cheapest and stronger than anything for weapon building
Double sided tape requires no skill and is very fast but is not the strongest bond (It's not good for foam to core bonds) It's also expensive requiring roughly a 3$ roll for every other sword or so.
Spray glue is quick and somewhat cheaper than tape.
PVC is not good in the winter, some people say it works just fine I've had some last and some shatter. I don't use it anymore cause it's not worth my time to build a sword that might outright break after the first battle. PVC is forgiving to noob weapon smiths so long as you get three layers of foam on there.
Fiberglass is expensive compared to PVC costing around 1$ per foot. 1/2" round cores will last you for a long time and can go through quite the beating, outlasting many lives of foam. They require a touch more skill to get them to be there best though. (you can also build a 4' red sword on 1/2" fiberglass but not much bigger)
Curved shield cores most often come from plastic 55 gallon drums. They provide crazy good defense but ultimately hinder your offense, Make them if you wish but do not rely solely on them for shields.
2' Heater shields are by far the most economical shield type and they will encourage the most aggressiveness from players while also building on footwork and defense. You can build these shields on a 3/8ths plywood core using what's called the waffle technique in this tutorial
http://www.dagorhir.com/forums/index.php?topic=12052.0. you'll use less foam per shield as shields are very expensive compared to most gear.