1) No. You can have more than one directive, but they only apply to the file prefixes given inside the <Files> directive itself - within the <>, that is. <Files> </Files> is the container, and it contains other directives to be applied to all files (regardless of subdirectory path) that match the given pattern.
2a) No. <Files> directives apply to all files which match the given prefix in the current directory and all of its dependent subdirectories.
Note that this <Files> behaviour differs from that of mod_rewrite, which works with URLs. Since mod_rewrite uses URLs, the entire filepath is taken into account. But <FIles> just works with the filesystem, using the name of the file(s), and doesn't care if it is (they are) in the current directory or in a subdirectory, or both.
The transition from working with URLs to working with filepaths is subtle. Most webmasters don't even make the distinction until they begin to work with mod_rewrite. The distinction only becomes obvious when you realize that you can use mod_rewrite to re-map everything so that your filenames and your URLs no longer need to have anything in common. (Not that you should, but you can). Mod_rewrite takes URLs as input and outputs (usually) filepaths. So it exists in both worlds - the URL-world and the filesystem-world. Mod_rewrite can be forced to output URLs instead of filepaths by using the [PT] flag; This is sometimes necessary so that other URL-to-filename converting modules can use mod_rewrite's output before content is served.
2b) Options and IndexIgnore, No (I think). RewriteEngine on, Yes -- needed in each .htaccess file.
There is something there at Apache.org about "inheritance" or something - it's been awhile since I dug through it. The general rule is that configuration directives apply to everyhing in a directory and all of its subdirectories, unless you override the higher-level configuration in the subdirectory. You can also disable this override-ability if needed. RewriteEngine on is not a configuration directive, it's a module-control directive, so it is different. (Hope that's clear) :o