Welcome to the Forum Tony! Looking forward to following your build.

In answer to your questions (from my experience..)

a. Is building guitars suitable mantherapy (and therefore supported in future by She Who Must Be Obeyed),
Yes, but you will struggle with the Ministry of Finance & War after half a dozen builds...

b. What will a guitar essentially designed by an 8 year old girl look like,
Pink or pink/purple. A pink or purple strap is also required. It may involve flowers or Hello Kitty

c. Does Dad have mad skills that have been dormant for 46 years,
Yes, we all have an inner luthier buried somewhere inside us

d. If a father and daughter who have questionable trade talent can build something together that's playable and looks cool, and
Most definitely and is good bonding time

e. Is it possible to turn an ST1JR into a short scale bass?
Not sure on that one!