Hey & welcome!
In general, just regular, repetitious practice will help gain finger dexterity & strength. But I've had success with these tutorials developed to help students that really struggle with these issues.
Trill Drills
https://www.guitartricks.com/tutorial/1829
Building Pinky Strength & Dexterity
https://www.guitartricks.com/tutorial/1292
Regarding the different fretboard scale lengths. I find that does not matter as much as the overall comfort of the neck profile (width & depth of the neck) and the action (the height of the strings from the frets). To be sure, scale length can be an issue. It is best to stick with one guitar while you learn the basics. But a neck with an uncomfortable profile & action that is too high are much bigger potential roadblocks for beginners.
For example, I typically play Strats with 25.5" length. But I also have a couple of 24.75" length guitars. It only takes me a couple of minutes to adjust from one to the other pretty seamlessly. But a Strat with a fat neck and, or terrible action is just hard to play! There's no adjusting to it in a way that makes it as easy to play as an instrument that is more suited to my preferences.
I encourage you to pick whichever guitar is the most comfortable overall & stick with it while you build your foundational skill. Hope that helps!
Thank you Christopher! I will definitely incorporate those drills for dexterity. I will also measure the action on all three and look up the neck profiles for each guitar. They all feel equally challenging at the moment, but I’m assuming that one should be easier to play than the rest.
Much appreciation for the quick reply!
