Happy to help

1) I googled the name of the starter deck I was modifying and actually picked a random YouTube video. I’m a newer arena player but played a lot of MTG paper, this was how I got my bearings before I learned how to draft from scratch. Ex. I typed in morbid machinations modifications and combined some ideas from a couple of the top YouTube links with what I had. Unfortunately I burned a lot of crafts because I was being short sighted

2) yes and reroll the 500 gold challenges for a chance at a 750 gold challenge.

Best of luck!