start with a OW certification class

 Fins.

 Call 'em fins.

 Or else. :-)

 As far as a mask goes, others will elaborate, but the only criteria is how
well it fits your face.

 After that, it's pretty much like asking which soft drink is best, i.e.,
personal preference.

 If you don't know or remember the term, a "low profile" mask is easier to
clear.

 Some folks like purge vales, some don't, if I liked the rest of the mask,
I would take or leave them as an option.

 Most people eventually wind up with an aftermarket mask strap.

 Most of us own one, a few carry one while diving, fewer yet wear it on the
mask strap.

 Both are correct, two different styles that may be available on the same
design of fin.

 Booties and straps are a relative must for colder water, but "full foot"
fins are preferred by some in warmer water.

 The majority here tend to advocate either Jet fins, or Mares Quattros, but
it's best to beg, borrow and rent several different types and try them.

 A pool lane will work for this, you don't necessarily have to dive.

Yes and no.  US Divers makes quality equipment.  They also make junk for the
tourist market.  Be sure you understand which one you're buying.

Some like them, some don't.  I've always found them to be more of a
hindrance than a benefit.  I find I can clear a snorkel easier without a
purge valve than with one.  On the other hand, I've found it can be hard to
find a snorkel without one that has other features I like, specifically, the
flexible section at the bottom that lets the snorkel stay out of my way when
I'm not using it and makes it comfortable when I am using it.

Generally speaking, people buy open heel fins for one of three reasons:
1. The dive shop convinced them they needed them (they're more expensive).
2. They need the thermal protection of booties and the open heel fins
accomodate booties.
3. They need the booties to traverse hard or sharp surfaces on their way to
the water and the open heel fins accomodate booties.

You'll note that the two reasons that actually mean something are based on
the need for booties, not the need for open heel fins.  In fact, full foot
fins are a less expensive and better choice for anyone that does not need
booties.  They generally fit with less  play and transfer energy better than
open heel fins.  If you don't want booties, don't buy open heel fins.  I use
Mares Plana Avante, Plana Avante TRE and Quatro Power fins, all in full foot
design.  The first two are good for both snorkeling and diving.  The Power
fins don't work well on the surface, but are more powerful, and larger, than
the other two models.

Lee