1> this is an ircd question and has nothing to do with Anope at all.
2> Short answer ... no.
3> Long answer .. no, in the event of a crash, nothing is saved .. A crash is just that, a very sudden and usually harsh full and unexpected stop. Saving data require an intentional dumping of data to hard copy while the application is still running.
4> The way IRC works is all channel data is destroyed when a channel no longer exists. Some IRCds like Nefarious have persistent channel modes to hold such information, but again, that data will likely be lost even if nefarious crashed.