You won't manage to do it.
To get that +14* to each mental skill you will need a Mutator level of 37 for each of the three mutations that improve your mental ability scores. Which means 17 instances of Limitless for each, to a total of 51 mutations spent on Limitless, followed by 42 mutations spent on the relevant mental ability score enhancers. Totaling 93 mutations. This is well within the potential maximum for the evolutionist before the 20 mutation boost, but leaves a relatively minimal ammount of mutations for other purposes.
All in all, it is quite simply too much expense for too little gain.
*The actual gain is +21 due to the bonus from the increased ability score modifier.
I'm not saying that limitless isn't useable. It certainly is. But for the most part it really isn't good as anything more than an early-access enabler, like that one Binder feat.
For your skill boost one, I recommend making sets of mutations that boost 2-3 thematically linked skills following the same overall mechanics as the skill booster mutations already in the Innate List, such as Pheromones and Extra Senses.