I responded to this whole post, then realized that the whole thing concerns Basic vs. Evolved Pokemon. So I'm going to open with the rules concerning that, and then start answering questions.
The easy way is to just ask yourself this question about a Pokemon:
is there another Pokemon card underneath it? If so, it's considered Evolved. If not, it's considered a Basic.
Note that what's written on the card doesn't matter once it's in play. You can have a Basic Evolved Pokemon -- Baby Evolution is the prime example. You can have a Stage 2 Basic Pokemon -- see cards like
Archie that let you play an Evolution card directly to your Bench. The stage printed on the card is only relevant for starting the game and searching the deck.
Level Xs are a minor exception to this rule. A leveled-up Pokemon inherits the evolution status of the Pokemon underneath it. So in this case, ignore the Level X card for a moment and look at the base Pokemon card directly underneath it. Then ask the above question again.
With that out of the way....
Thou Shall Sleep said:
Can you rare candy an evolved chansey?
No. Rare Candy says to choose a "Basic Pokemon" in play. Chansey is no longer a Basic if you evolved it.
Thou Shall Sleep said:
Can you do it on the same turn?
I'm not sure what "it" is. I'm going to guess you meant Baby Evolve from Happiny to Chansey and then Rare Candy to Blissey. The answer is no, since you can't use Rare Candy at all if Chansey is Evolved.
Thou Shall Sleep said:
Then since chansey is evolved, can boost energy be attached?
Yes, if it's Evolved.
Thou Shall Sleep said:
Since lv.xs are neither basic or evolution pokemon, can boost be attached to them?
See above. Level Xs inherit the evolution status of the Pokemon they're played on. So if you leveled up an Evolved Pokemon, you can attach Boost to it.
Your question is referring to the
deck searching rules on Level Xs -- a Level X isn't a Basic or Evolution card
while in the deck, but once in play it takes on the status of whatever it was played onto. The deck searching rules
have been discussed recently.
Thou Shall Sleep said:
When garchomp lv.x rebirths something it counts as a new basic. So boost can't be attached right?
I normally don't comment on something concerning a ruling question until there is an official English translation. But I really think you can answer this question yourself, if you've been reading up to this point
Thou Shall Sleep said:
Cradily ex's primal vibes forces you opponent to not evolve{except if he uses wally's training. Does this mean you can't level-up also?
Leveling up is not evolving. Cradily can't stop it.
Thou Shall Sleep said:
Nidoqueen FRLG's power lariat does +10 damage for each evolved you have in play. So if you have let's say a fully evolved garchomp, then does it also count the gabite below the garchomp?
No. Only the top card counts. Garchomp is one Evolved Pokemon, not three separate Pokemon sitting on top of each other.
Thou Shall Sleep said:
Does power lariat also count leveled-up pokemon?
If they're Evolved, yes.