I cannot reproduce any of these, though I haven’t tried to block any senders.

I’ve never seen messages not show up in a search or in all mail. It doesn’t search spam or trash by default, but you can override that by adding e.g. “in:trash” if for some reason you needed to include those. It shows me the sender email address just fine when I tap on the header. It also marks a message as read immediately on opening it. I don’t see an option to change this on Android, maybe it’s a per-account setting you can change from desktop.