The 2019 ES manual is a nice package now even though it still lacks alloy wheels. Personally, I would take manual transmission over alloy wheels any day. Much easier/cheaper to upgrade wheels than change out the transmission on any car.
I think the 5 speed manual is a hoot to drive. I am not a small guy, & I don't find the Mirage uncomfortable at all. I've never sat in the back seats, but the front seats seem perfectly fine to me. I really wouldn't change anything about them.