entirely reasonable. i just would've liked to see an attempt to bridge the two arms of the franchise.The aesthetics are "21st century futuristic", which is essentially what they did in the Kelvin timeline. Copyright laws / intellectual property probably prevent them from reproducing the ship designs too closely. That being said, the designs we see do match up fairly closely to the ships from ST'09.
As for actors, I'm less concerned about getting the same people. I always though Ben Cross was too old to be Sarek of the 2250s. Ditto for Bruce Greenwood (especially now). James Frain is closer in age to what one might expect a younger Mark Lenard looked like. Winona Ryder is probably tied up with Stranger Things S3. And there's no way they could afford Zach Quinto.
The only actor who I think would be fun to see in Discovery is Faran Tahir (Robau). A look at his IMDB resume suggests he's largely been working in TV recently, so he'd probably be affordable and potentially available for a guest appearance.