Did you do the stencil? If you did then you know what kind of paint was used. If it's acrylic or latex, a good blockout primer should be all you'll need. You might get away with not priming but I'd hate to wake up in a few months to find that it bled through. If the stencil is oil - there are oil paint sticks and paint pots that are in decorative painting - then you REALLY need a blockout primer for sure. The other thing to do whether the stencil is oil or latex is to lightly sand it - just a few big swipes with a fine sanding block. You may not see it now but the shape of the stencil can telegraph through a new coat of paint.

gray is a tough color to get right. we painted 1/2 of our house with SW Repose Gray. It's great in some area, but in some area, it has a teal cast to it, probably due to the CFL fixture. I might have to replace that light fixture in that area soon. BM Revere Pewter is another popular grayish color, but your reddish brown cabinets might bring out the green undertone in RP, so make sure you get a lot of samples and see how they look with your lighting in your kitchen. Good luck!

If you like staging, why not get into it? I purchased my sofa from a woman who did it for a condo complex, and she was busy. She had her 2-guys-and-a-van that she used, and she purchased high quality stuff off Craigslist and then sold it (she didn't do storage). I believe you just have to introduce yourselves to realtors as a kind of internship (prob. super low pay at first, but that's a very positive perk for the realtor to offer his/her clients...Of course you would just have to use the clients stuff if you don't want to "own" anything. Many folks (not you clearly) need an objective third party when getting a house ready to sell (the queries on the subject here are proof of that).

It's impossible to be sure just from a picture, but it looks to me like your cabinets, counter, etc. are well-made and were probably expensive when they were installed. Doing a quick patch job of redecorating by painting and putting peel and stick tiles over the backsplash is going to give you a lighter kitchen, but it will turn it into a cheap-looking kitchen in the process. Of course it's up to you what you can tolerate. If this were my kitchen, my choice would be to stick with a high-quality look that's out of style (especially since it's fairly neutral) until I could get a firm vision of what I wanted to do AND make sure I had the budget to do it right.