stretch vs. windup

"... risk of seeming stupid..." You sound pretty knowledgable to me! In fact, your post probably qualifies you for top 10 % in my LL.....

Basically your are correct on everything, except most BB people I've talked to and research I done, feel that a windup will add a couple MPHs to a top caliber ( HS and above).

LL....??? probably not much difference except balance and or rhythm... although I my son adds one to 2 MPH when we clock him...

I always teach the stretch position first ( for the reasons you describe) and usually require players to only use it for the first year maybe two....As they master that we will add the windup and let them to build up a rhythm...

When you do teach the windup.... go and read rule 8.01(a) especially the part ....

"...The pitcher may have one foot, not the pivot foot, off the rubber and any
distance he may desire back of a line which is an extension to the back edge
of the pitcher's plate, but not at either side of the pitcher's plate. With his
"free" foot the pitcher may take one step backward and one step forward,
but under no circumstances, to either side, that is to either the first base or
third base side of the pitcher's rubber...."

So many kids step to the side....It could conceivably be called a balk! and as you can see above it is illegal....(be seldom called) Of course they should be in the stretch.... except with Bases loaded...