While I'm certainly not one to stop you - I'm planning on roughly the same thing - but like, Thunder kinda requires Mardook and Mammon to be good. And that's WAYYY in the future. Even then it's quite lacking in tools, it just covers the debuffs... and even that requires help from your Soul. Are you sure you want to build a Thunder team?

I mean, I'm pretty sure that with three Miracle tickets, you could probably build better teams in other elements.