Here's what I know about this beer, giant post ahead:
I've successfully cloned Yellow Rose after many tries, and the only thing that has made it real was their house yeast. Trevor Brown (founder of Lone Pint) told me that the only two secrets they keep are their water and their yeast.
YEAST
I managed to get some of their yeast by simply asking via e-mail. Trevor was really nice and accommodating and invited me to come by one morning during a transfer to get a jar of slurry. If anyone chooses this route, definitely be aware that you're going to a functioning brewery during working hours so dress accordingly - as in, wear clothes that you don't mind getting yeast, beer, and caustic on. You also will be in their way. Not that your presence will be an intrusion, but the brewery is so small that you will probably be stepped over at least once. Basically, get in and get out. You can talk to the brewers on a tour day if you want to chit-chat.
Trevor told me that their yeast isn't one you can buy in stores. I'm not sure if this is still the case, but it might have been when they first adopted that yeast. They founded the brewery in 2012, and with EthanH's information that the LP guys said they used a west coast yeast, it could be that a yeast from the west coast has come into production since 2012 that wasn't available then.
I've also taken that yeast and repitched it into 2 other beers, so I have a good idea on what flavors the yeast puts out, and I'm still puzzled as to its origin. It's definitely
not Chico, probably not 090 either. Could be Pacman or 1332 Northwest Ale. Whatever it is, it's not a neutral yeast by any means, and is a very poor flocculator. There is a lot of bread dough, pale stone fruit, and a little tartness. It really accentuates hops, especially the passionfruit, mango, lychee "tropical" category that Mosaic falls into. It could also be a blend. Can't rule that out as a possibility.
WATER
I've been to the brewery, and they have a water filtration system, which I'm guessing is RO. Looking at the pic, it could also just be carbon block filtration, but they have some other tanks against the wall which appear to be connected. They also have an extensive supply of water salts. I imagine they build their water from scratch, and it definitely has a focus on Sulfate. They have more bags of gypsum than anything else.
Their system
MALT
I love the DeFalco's guys, they're my LHBS, but their recipe is completely off. It was the one I used when I started my journey to clone this beer, and there were not enough hops, no dry hopping, and the wrong malt. I would urge people to not use that if they want to clone Yellow Rose. They also only say to boil for 60 minutes. For my first try at that I followed the recipe to a tee, and I got a hoppy DMS bomb. Whoops.
Weyermann Pilsner malt is mandatory here, hands down. No other malt I've tried even comes close to the flavor of that one. It's also the malt they use, so there's no reason to use anything else if you are attempting to clone it.
HOPS
I've always used pellet hops because I can't find any whole Mosaic hops, but I don't think it makes a difference. My latest brew, the successful clone, had just a bit less sharpness to the bitterness, which could be the difference between whole and pellet, or it could be water, or it could be that I didn't add enough bittering hops. I focused more on the late and whirlpool hopping. I used 7oz. in my 6 gallon batch, but I could have easily used half a pound.
RECIPE
For 6 gallons at the end of the boil (5.5 into the fermenter), and 70% efficiency:
OG - 1.064, FG - 1.014, 6.6% ABV, 64 IBU (Rager)
90 Minute Boil
90 Minute Mash @ 150F
14.5lb Weyermann Pilsner malt
All Mosaic hops
0.6oz @60
1.0oz @20
1.4oz @10
2.0oz @Whirlpool/Hopstand for 20 minutes (can be more)
2.0oz @Dry Hop 5 days (can definitely be more)
Lone Pint House Yeast (sub with fruity, hop focused yeast)
I used my standard "Pale & hoppy" water profile, but it could probably use a little more sulfate.
Calcuim: 96 ppm
Magnesium: 10 ppm
Sodium: 8 ppm (it's just what I have in my water)
Sulfate: 200 ppm
Chloride: 55 ppm
Bicarbonate: 16 ppm (again it's just what I have)
Add acid to bring pH down to 5.2-5.4 (I aim for 5.4 in my hoppy beers)
Side by side, I've never brewed a beer as cloned as this one. The only difference was that mine has just a touch less of a sharp hop bite than LP's. Other than that, the beers are identical. I ended up pouring one glass into the other they were so similar.
Sorry bout the megapost, I've tried to condense all my knowledge on this beer as best I can. Hope it helps someone. Good luck!