I tried finding this info but I must have missed it.
I'm not sure.
Here are my questions!

Mystical Essence gives you 4 trait points.
Right?
That's the biggest one I've seen.

Is it possible to generate a pet with 8 Trait Points?
Can more than 1 essence be consumed at a time?
Or will it only consume 1 and then the max is 4.
Or is there a bigger essence I haven't seen?

The highest essence you can currently get is the mystical essence and it can generate 4 trait points. You can only consume one at a time. So, yes, the maximum trait points that can be generated is 4.

First of all, both Enhanced and Mystical Essences give 4 trait points. Just that the Mystical Essence is 100% accurate with the hex colors you entered. It is not possible to generate a pet with 8 Trait Points. Only 1 essence can be consumed at a time.

So I guess breeding is the only way to get a pet with more visible traits.
Do visible traits appear on offspring, or only traits that are chosen as carried?

I just had a design I really enjoyed but I doubt I can get it now.
I've never been skilled at this breeding stuff,
o':

Is there a breeding guide somewhere?

Try https://www.sylestia.com/forums/?thread=370 for a guide on breeding.

If you're wanting a more in-depth breeding guide to show you have to get from essences to a 6 visible offspring, Xavion's 6 visible breeding guide is probably your best bet. It's a lot of reading, but it gives you all of the basics, plus the in-depth for if you want to do project-type breeding.

Thank you!