Okay so luckily there was more than enough at my pre-release so I decided to attend to round off the numbers. I can confirm that the deck lists in this article are false to a degree. They are indeed partially random, but also helpful for the pre-release. In this set's case anyway. The card choices could have been better, even more beneficial. Another thing I'd like to point out is the fact that these boxes seem to guarantee at least one Pokemon-EX or BREAK. Tyranitar seemed to take up a majority of the "mini decks" people got, almost like a specific rarity. Tyranitar being Common, Zygarde being Uncommon, White Kyurem being Rare, and Moltres seeming to be the lowest chance. But I'm sure this is just something to do with the packaging and shipment.
Pull-wise my box granted me a Full-Art Glaceon EX in the first pack and an Umbreon EX in the last pack. I also got two Delphox Breaks. Pretty much everything in the set was pulled at the pre-release except Team Rocket's Handiwork Full-Art (Which is a bummer cause I literally went around asking everyone if they had it :'C )
Also no one was happy pulling a Tyranitar Deck because it was extremely useless. Delphox and Carbink were pretty good choices.
The place I go to ran an unofficial pre-release on Saturday as well as the official one on Sunday. We had eight people show up each time, pretty much the same people at that. I also saw a box opened beforehand two days before the pre-release so we had an idea on what to expect. They originally thought the promo couldn't be used though until I read the sheet that came with it to confirm that the promo could be used. This box contained a Delphox BREAK and Zygarde EX. Those are on hold for me until they can sell them .
However I can tell you that these do NOT guarantee a Pokémon EX or BREAK as there was at least one person at my pre-release who did not get anything of that sort. However the chances are high as my first time I pulled Regirock EX (worked okay in my deck with two 50% Zygarde's, Hawlucha and Lucario) and Omastar BREAK (couldn't use it). I also won that one ultimately and got two extra packs for winning and got a second Regirock EX. The second one only gave me a Carbink BREAK and I had no Carbinks to use it. The chances however were pretty high, I too had someone pull a Full art Altaria EX and an Umbreon EX.
Most of the mini decks I saw seemed to have White Kyurem, including my first one. In addition I also had a White Kyurem in the booster packs. The person who built their deck across from me also had a White Kyurem deck with a second obtained through the booster. My second one sadly was Tyranitar (I wanted Zygarde) though one of the packs had yet another White Kyurem. The biggest problem there (aside from the fact I think the card in general is horrible) is that the 'deck' comes with one Larvitar and one Pupitar. Unless you get at least one more of each through your packs it's virtually impossible to rely on. Delphox was really good though and it was funny to see a Carbink BREAK played on the Safeguard version against Altaria EX. I myself got into a Dewgong vs Dewgong match of which I barely won. Chaos Town was a big help during the last two turns since I elected to take the side that prevent sleep and confusion, the two status effects Dewgong could deliver.
I hope that is one thing they change in the future, no card should be a promo for their 'box decks' if it has to be part of a huge evolution line that they don't provide decent support for (at least they did this for Delphox), and in fact I think it shouldn't even be one that has an evolution line at all so that way using the card is much more viable.
Also ended up trading to get M. Altaria EX full art, Genesect EX and Diancie EX, so it was a nice weekend. Looking forward to trying the next pre-release toward the end of August.