Elfstone, if and when I do get a kick for it, I've got a few questions for you.
1. I got the standard Tenergy 18650s with it. I think I read on the site that this won't work with the kick even if the extension is purchased. Is that right?
You should not use a Kick with ICR batteries, only with IMR. It's a matter of safety / ability of the battery to supply the required current, not of size or of whether it works or not. I can only recommend AW and Panasonic, really.
2. Will my Tenergy charger be able to charge the batteries it does require? This may sound like a stupid question, but I just haven't owned many devices.
I don't know, but I think so. Look on the back of the charger - if it says Output 4.2 V and ~500 mA it's a go. It also has to have an auto-shutoff at target voltage which all Li-Ion chargers have.
3. How difficult is it to remove/replace the battery with the kick in there? It looks to me like a fragile sort of chip (the kick does).
This is a non-issue with the Legacy. Again, for IMR batteries you will most likely need 2-3 of the washers that come with it. IMRs are a bit shorter than protected ICRs. Take a look at the Basilray video to see how to put the washers in the switch. If you want to use the 18650 with a Kick you also need the extension tube. If you don't have / don't want the extension tube you'll need to use 18490 with the Kick. Now, you put the Kick at the top end - unscrew the top cap, the one with the atomizer connection and stick the Kick in there carefully not to let the tiny spring catch in the threads. Then you will change your battery through the bottom cap from then on, and the Kick will always stay in place. If you want to adjust the Kick - take off the top cap and turn the Kick adjustment screw. It's as if it were built in, really.
4. I'm a bit of a flavor changer. Maybe 4-5 flavors throughout the day. Since apparently different juices taste different at different wattages, how often would I need to reset the kick?
Depends. I now vape only DIY and in fact my all-day vapes are good at the same wattage for me so I don't adjust it all that often. Again, it's really easy, because you don't have to remove the battery to do so. The biggest power changes I need are usually between sweet/bakery and fruity as well as between "tobaccos" (which I no longer vape) and non-tobaccos. Also I tend to lower the power if the menthol is strong in a juice to avoid the extra-throat hit.