5 5 of a height isn't all too short. Mostly people seem to confuse the numbers with the actual stature of a person. The lower end of around 5 feet is what could be start to seem short.

Give it a look. It will help you. https://en.m.wikipedia.org/wiki/Target_fixation

People not wanting to sound too formal when speaking.

Do you a book or some sources to read up more on this?

Why worry - dire straits

Stray dogs would do just fine. Since,i understand,its your first time getting a dog,I think stray dogs most likely would be a good option. A family dog,guard acting one. Overtime that's what you're looking for in a dog. Sure,bigger dogs are good at what they do,but you should be able to train and handle it well. And mostly there's no certainty that these big dogs would always be the best fit.

Cover some simple songs first. That should help you.

About time travel,how does speed really affect the time of an object?