Thru hike for two, best tips?

My Fiance and I are planning to do a thru-hike in mid-march NOBO.

The current budget is $8000 all-in for both of us, with the current questions being,

1. Should we each have an SOS button or just one?
2. What food schedule do most people have? And how much of our budget should we put towards that?
3. What are your normal pack weights? The current plan is 35 for her, 45 for me (after all food and water at full load, Dry weight is trying to be around 20 lbs), and am curious if that is far too much or too little?
4. Bio-lite for camp stove/charger/battery pack or Solar Panel with Battery pack and fuel with BRS3000T? The weight should be about the same, but I haven't relied on a bio-lite and don't know the reliability of those extra functions.
5. Is 3 liters of water per person generally enough outside of desert stretches?
6. What was your "luxury" item?
7. I'm planning to be on the long side, and a 7-month hike, how long did it take you to hike it? (Or estimate if you've done sections)
8. Is REI with a membership card the best way to purchase items, or are there comparable companies that I can trust the customer service while I'm on the trail?
9. Iodine and/or water filter? Sawyer mini and Lifestraw as a backup worth the weight?
10. Do you have a spreadsheet or list of gear that you used that I could use as a reference?
11. What are the absolute critical tips that you fellas have for a successful trip?

I know a lot of these are conditional on what I feel is worth the weight, and risk, and budget, however, I'm curious about your point of view, rather than what could be good for me in a situation. What are YOUR answers?

Sorry for the flurry of questions, I am wanting to be as prepared as possible.