Which exeguttor to power up?

Honestly they're both pretty boss. I'd say that it depends on whether you need a strong defender or if you need a strong grass type attacker. The one with psychic will be a monster defender but the solar beam should shred vaporeons on attack. That's really the choice it comes down to.

It depends whether you want an attacker or a defenser. Though it is confusion instead of zen headbutt with solar beam, it is still a strong Vapereon counter. The one with confusion+phychic is one of the best defensive move set. If I were you, I probably would power the latter one up. The reason is that confusion+solar beam is dominated by zen headbutt+solar beam(unless you want to use it in defense), and in the future if you do have one with z+s, c+s will be less useful. However, confusion+phychic is not going to be replaced even if you have a new exeggutor with other moveset. It is always one of the best defensive exeggutor.

It makes a consistently strong attacker vs all defenders, I love solar beam. It's like a nuke. I'd power it to 2000 or so and save your candy in case you hatch one and want to power your defender.

C/SB its an B attacker and still an A defender. C/P its OP too, but i would power the C/SB one.

where is this park?

89% lapras/snorlax/dratini ok, but 89% exxegcute Never!
you can find best easy.
just wait a littel.
i got 2 exxegcute 2K7+ 98 and 96% conf/sb
i am very happy for not using candy before! i dont up me 91% or 80% exxegcute