hadn't heard of this site before. looks like they have a lot of good stuff. "World’s largest Science, Technology & Medicine Open Access book publisher.
Publish, read & share novel research."

yes, correct. I guess per reviewing could be done differently, have seen in academia.se some questions on that topic so you might get that for free by asking.

if they do a good job at editing formatting and such, the price can be justified, when it is required, and assuming editors are focusing on scientific papers and have general sufficient background for that kind of work.
But that all does not matter, sci-hub is up and back, embrace the access

totally missed that thing, did you seen it https://en.wikipedia.org/wiki/%CA%BBOumuamua
an asteroid from outer space, shaped like space ship, with relatively close flyby(60 l.s)