I'm not a Slowbro expert so I'll just give you my 2 cents on Eggy.
Psychic has been nerfed so I do not advise powering up those with P. ZH/SeB has no real use. Considering you have an awesome C/SoB which is a great defender (and can also help for attacking), you can safely power up your last one with ZH/SoB which is a good attacker.