Hi, and welcome to ECF!
Good choices for starting - although you'll soon find that you need at least two of everything. One to use while one is charging, and sometimes things fail (or we break them

) Don't want to be without the means to vape.
At this point, I'd recommend you just get some spare heads / coils for your mini PT2. You want to get comfortable with your setup before you start modifying stuff. The factory heads come wicked with silica, and with proper care can last a long time. So no need to rush into rebuilding.
Cruise ECF and utube for the procedure to clean and dry burn the coils. Simple to do, and returns them (usually, and if done right) to factory performance. And removes all traces of the previous flavor.
You can vape a flavor until the vape starts to fade off. Then it's time to clean / dry burn, or replace the head. Some flavors will gunk the coil in just a few fills, some will go a long time between cleanings. There's no really good average that can be given.
In general, a thorough cleaning under hot running water will get rid of most of the previous flavor, but not all. For that, you need to clean and dry burn. But going from the cotton candy to hawk sauce would probably be ok. From light / sweet to a heavier flavor isn't a bad transition. The other way, well, you might not get the new flavor for some time
You'll probably find the the flavor wicks - the two loose strands under the chimney - are not reuseable. They do have to come out to dry burn. I usually just replace them with a strand of 100% cotton yarn. Or you can tease out some cotton from sterile cotton balls, swabs, or whatever. Just note the size of the flavor wicks and make a
loose roll of cotton about the same size. Too much and you'll choke the flow, causing dry hits. Too loose, and the PT will probably leak.
And don't forget to rinse the tube while you're cleaning
(Also, MBV mixes when you order, so they will need some steeping time. It can make a BIG difference in flavor!)