Great Encounters
Great Encounters, like the first two Diamond & Pearl era sets, has one Pokémon LV.X per box on average. The rarity table looks as follows:
I talked about the reverses in my previous post. The selection of RE2 cards appears random and includes one reverse rare holo (Pachirisu), two reverse rares, six reverse uncommons and ten reverse commons.
For the holos, they would all fit 11 times on a 121 card sheet and I have no reason to assume there were any artificial rarity differences introduced. Since there are only 11 of them, they are actually marginally more common than some of the non-holo rares.
As mentioned in my previous post, I was able to nearly completely reconstruct the rares sheet, and feel confident I identified the five R5 cards - their choice is obviously not random.
I did not look at the uncommons, but I reconstructed the commons sheet. Interestingly, Lunatone is only printed twice on the sheet, making it rarer than the other commons. I would guess this is by mistake, since Solrock appears three times on the sheet. The commons sheet looks as follows:
† Mankey, Cacnea, Slowpoke, Porygon, Koffing, Kakuna, Torchic, Whismur, Feebas, Treecko, Lunatone, Togepi, Clamperl, Ekans, Volbeat, Zigzagoon, Solrock, Luvdisc, Illumise, Igglybuff, Slugma, Mudkip, Caterpie, Glameow, Makuhita, Unown L, Weedle, Snubbull, Krabby, Houndour, Treecko, Porygon, Buizel, Mankey, Drowzee, Jigglypuff, Baltoy, Torchic, Wingull, Swablu, Koffing, Tangela, Slowpoke, Zigzagoon, Lunatone, Makuhita, Clamperl, Whismur, Caterpie, Ekans, Togepi, Feebas, Slugma, Cacnea, Luvdisc, Glameow, Unown L, Solrock, Kakuna, Mudkip, Igglybuff, Houndour, Weedle, Krabby, Porygon, Baltoy, Volbeat, Drowzee, Snubbull, Buizel, Illumise, Makuhita, Jigglypuff, Wingull, Caterpie, Koffing, Zigzagoon, Mankey, Treecko, Slowpoke, Swablu, Torchic, Tangela, Clamperl, Glameow, Krabby, Weedle, Ekans, Whismur, Mudkip, Cacnea, Slugma, Porygon, Feebas, Kakuna, Baltoy, Togepi, Unown L, Volbeat, Krabby, Igglybuff, Solrock, Illumise, Luvdisc, Snubbull, Torchic, Treecko, Makuhita, Zigzagoon, Wingull, Caterpie, Drowzee, Jigglypuff, Mudkip, Tangela, Baltoy, Glameow, Houndour, Weedle, Buizel, Swablu †
As to Pokémon LV.X, my Youtube sample yielded 6 Cresselia, 4 Dialga, 2 Darkrai and 2 Palkia.