Is it legal to create a Website template for themeforest from available Photoshop template after buying.
No. You need to make a deal with the owner.
No, but I think If you buy the Extended License perhaps you can, any way ask the author to know more, the license matter is still a bit ambiguous
It is not about the license. Even if you buy an extended license, you still have to have an agreement with the author to sell it on the marketplace.
To create an individual website for your client or your company or for your personal website, yes. To redistribute it, no.