On the Wizards. The two Blue Wizards (Ithryn Luin) actually did come over in the 2nd Age and then headed east. They could be part of an arc in the show.
Tolkien kept adjusting the timeline of the Wizards and Glorfindel. Near the end, he had Alatar and his friend Pallando come over sometime in the second age. Same with Glorfindel. The best estimate is around the time of the forging of the rings. Say 2nd age 1600.
Glorfindel being left out of the Lord the Rings movies was a big hit for me. Having another elf with power somewhat on scale (but different) of Galadriel was very cool. Comments about how he couldn’t be sent with the Fellowship as he would be like a beacon to Sauron and the Ring Wraiths.
If you don’t know Glorfindel, he was a Noldorian Elf of the Light and a Captain of Gondolin. He died taking down a balrog then. He came back to Middle Earth sent by the Valar in the second age. He fought the servants of Sauron for the next 4500 years or so. Ring Wraiths were terrified of him.
He can and should be part of this new series.