Random Zeo questions

[Cestro]

After watching a few episodes of Zeo, I started to think of questions regarding the series from a within universe standpoint and a production standpoint. So here is a series of random questions that I hope there are answers to.

In universe questions:

1) Was it ever mentioned what African country Tanya is from?
2) Dose anyone understand the time travel that led us into Zeo?

Production questions:

1) Why was Ernie's Beach Club on the lake? I mean, they were filming in Los Angeles at the time, could't they have gone to an actual beach?
2) Why was it that only the actors for Cestro and Delphine returned though out the run of Zeo? Could they not get the other Alien Ranger actors or did they not want to get the other actors?
3) In relation to the Tanya question, has Nakia Burrise ever stated why her character is from an African tribe, yet she played the character as a typical American teenager?
4) Why was it necessary to introduce the Machine Empire as the new villains? Granted they were using Sentai footage, but they eventually brought back Zedd and company with original footage, so why not just keep Zedd and Rita all season?