Which of the two jobs is better for a frontend Dev:
1. React project, stressful, bad communication, depending on bad internal libraries
2. WordPress theme building, higher paid, promising startup with stock options

Depends what is important to you.
Is it more important to you, to have a good income, or is it more important to develop on interesting stuff.

1) sounds like a challenge, on which you will learn lots of stuff, but it might make you miserable working on that project
2) sounds like a relatively secure income for a period of time, but you provably will bored working on it.

tbh both options seem to be crap

I think you are asking whether the crappy job or the promising one is better. I'm going to go with the promising one.

>wordpress startup
>2018

>$5 says it will be shit

@sharktits their main product is an app, WordPress is for their website

@platypus it's more promising business, but WordPress doesn't sound so promising as react, technic wise

@Xo-oY I believe that WordPress is adopting React, so, two birds...one stone?

@platypus yeah if they have such a plan to...

Depending on where you're at in your career, you also want to consider your personal growth as a developer very, very, very carefully.

Never settle for money unless you've got kids you need to sublimate your own interests for, or until you're at the end of your career, and are ready to cash your chips.

If this is still quite early in your career then don't even think about settling into an easy job - it will turn you into the most boring dev, completely out of their element for any meaningful conversations.