[One (M7) Q&A, Help & Troubleshooting] Signal2Noise:
Hi there! Allow me to welcome you to the rooting world! I'll do my best answering your questions. Not to come off as someone who's pompous, I've been using a rooted device for nearly 6 years now, so I've been through the woods quite a bit. I've had my HTC One since June of 2013.

1. Even though sometimes it's looked at as "okay" to dirty flash (flash one ROM over another; this method is mostly used when updating a ROM and the two ROMs are on the same version of Android), I don't take any chances. Besides, if you flash more than one ROM on top of another, it can cause your device to get super slow. So here's my rule of thumb: Almost always wipe before flashing, unless it's a minor update to the ROM you're currently using. Also, when in doubt of whether or not to wipe before flashing a new ROM, ALWAYS DO IT. Haha, better than having a very expensive paperweight! Flashing multiple times in a day isn't a bad thing, as long as your phone is plugged into some power source and you wipe your data and cache before every flash. One thing to keep in mind though, for a ROM to "settle in" to your device, the battery will drop excruciatingly fast the first day you have a new ROM that you decide to keep. I personally let my phone die after I decide to stick with a ROM and leave it off while charging to 100%. Obviously, this can't be done by most because of time restraints and busy lifestyles, so just be aware that you will have pretty... misleading battery results for the first few days of having a new ROM. It's simply optimizing the experience and what you do on your phone around the battery. So to sum up, wiping and flashing is all good as long as you're careful, but don't expect the battery to last you all day for the first few days after deciding on a ROM.

2. This sort of thing depends on the ROM and how the Aroma is set up by the developer. Most of the time, the answer is that you can go back in later and change things at the expense of minor battery issues and sometimes, depending on the modification, it can stop your phone from working correctly. Because of that latter fact, I usually play it safe and wipe before flashing to make the modification to the ROM. If you're installing a separate file to modify the ROM (aka, a mod) then flash it after the ROM is already flashed. A real advantage to having a separate, flashable mod is that you don't have to wipe before flashing it. Just flash it after whatever ROM you plan to use is in place.

Misc. tips:

- Try your best to keep your firmware as up to date as possible. Because we don't get notified of when this updates (roughly every 4 or 5 months), it's our responsibility to make sure we take care of the firmware asap. Not updating it can result in poor performance, low compatibility with newer ROMs, and bad battery life.

- Never, EVER flash more than one GApps package on top of one another. This can cause a ton of issues.

- Speaking of GApps, always flash them (if necessary, of course) after the ROM is flashed, but don't reboot the phone in between those two flashes.

Don't worry about the "irrelevancy" of your questions, man! :D We were all new to this at a time too, and back then, I bet most of us wished this sort of information was given to us without attitude or the "this guy's a noob" mentality. You should be all good to go! If you have any other questions (or if you want any ROM/mod recommendations) feel free to ask, my friend!