Kong, the WG Commander-in-chief, is residing in Mariejois. Im pretty sure he is the main protector of the Tenryubitos (After timeskip he might be too old though) I guess, despite his age, he is still on admiral level. Probably similar to Garp.
Anyway, they must have some beastly bodyguards besides him. Maybe its even CP-0 who is responsible for this? Maybe the 3 individuals we saw at dressrosa weren't all of them. And after all, Dofla is somewhat connected to the Tenryubitos, so that could fit. Or they have some other specially trained corps. I also like the idea of Issho and maybe Green Bull being former bodyguards!
About the tenryubitos themselves, I'm not sure. To be honest, i don't believe that they have any strong individuals among them. I mean thats why they have the Marines, the executives. The Gorosei on the other hand, might be a different call. They could be really strong, or at least in the past they have been, but i don't really know if they belong to the tenryubitos directly.
The tenryubitos have always been living a boring, safe live in Mariejois, being guarded by the Marines and special forces probably. There would be no need for them to get strong, as opposed to Dofla. He lived a completely different live as a pirate, he doesn't belong to this thread as you´ve already said.