Apple just offers three simple choices at the same price point with upgrades urged every 3 - 5 years in order to maintain their cashflow. That said, I'm editing 4k film in ProRes422 with sync sound on a late 2013 8GB 2.5G i5 Macbook retina (Final Cut Pro X / Avid Media Composer) so your option 2 should be more than enough for the next few years. Are you wedded to the Mac OS? You could get a PC and hackintosh it. If you're not wedded, the XPS13 running Windows 10 is a lovely little machine and can equal my i5 8GB Mac in specs for around $1100. Very small, light, great battery (best battery life is on the non-touch version).
Yeah, starting to lean towards option 2. I'm just not sure how much the processor and graphics card affects the performance. I'm stuck with FCPX because of my 4gb memory right now and it crashes pretty often which gets super frustrating. Somehow changing the text color triggers that :( Ideally I'd switch to Premiere pro and get some color grading software which can be intense. I would not what to invest the 500$ and realize the problem was with the graphic's card all along, you know?