Does Toei approves the deal ?

Yes? It's their franchise being adapted, they have to approve of all parties and practices involved. Hell, I think this is why ToQger is a thing, they knew what Nick's policies meant for PR no longer getting to be annual and decided "let's be experimental" and will always make sure there's a Sentai that aesthetically can be adapted easily to the western audience. Kyuranger might be that with how the stacking cubes thing of ZyuOhger could cripple the marketability of the Mecha in the West just like how Ninjas are more popular here than Trains.

If they didn't, do you really think Fox, Disney, and Nickleodeon would be able to avoid heavy class action lawsuits? Also, every show that has been in the US, has in the credits, "With permission by Toei" somewhere therein.

What about the 2 part season ? Toei approves too ?

Yes. That's what I just said. Toei, because this is technically still THEIR property, has just as much say on negotiating contracts as Saban does.

And also why I'm certain they went ahead and did ToQger, because now they can and can permit Saban to start skipping seasons.

I don't think that is true since Super Sentai is always made for the Japanese audience. I don't think they make any Super Sentai with Power Rangers in mind. I think the PR homages in Go-Busters was something for fun to show respect for the series outside of Japan. Going from what I'm told that Toei does get some money from the licensing fees from Saban, but they don't get every dollar from Power Rangers.

Think like a franchise. Toei is the parent company, and Saban is an offshoot. Saban will pay "Franchise fees" for each show, but considering that the SS/PR series are so unalike Toei can only get X amount of dollars from Saban profiting.

Most Sentai series are 50 episodes long. American TV doesn't work like that. They're going to cut and make it into another series.

Aren't some PR seasons brought back over to Japan?

I remember some of them did get dubbed. I recall the last PR show that got a Japanese dub was Samurai and Super Samurai. I hear some Sentai fans did like Lost Galaxy over Gingaman and enjoy In Space.

SPD got a dub too, I thought