Question about #1: Where did the photons originate though? Did the Andromeda Galaxy create its own, or were these bounced off and we see (basically) the reflection?

The photons almost all originated in stars in the Andromeda Galaxy. A very small number reflected off of gas in the interstellar medium, but nothing your eye could detect.

Which language though? Coming from someone who knows a bit but doesn't work in the field.

I would say Python. Easy enough to be a good teaching language + a huge ecosystem for real work, spanning everything from web dev to machine learning.

I second the other suggestion - Python. I think its a great language to learn first up. I feel its biggest strength is its excellent standard library and ecosystem Python allows you to do really cool things with minimal frustration. This is important because once a person gets past the basics what keeps them hooked is doing cool things what they've learned.

Its gotta be JavaScript. Given Meteor, JS is all you need to get an idea out the door.

To get an idea for a web site out the door. Not all ideas are web sites.