(1) Have you tried System > Preferences > Internet and Network > Network Proxy and set address ranges in the Ignored Hosts tab?
(2) I've never bothered with face browser, but GDM (which manages graphical login) is being completely re-written and is still missing a few features at the moment, so that may be why.
(3) As posted above, Plymouth does not yet support a wide range of video cards by default, although future versions will expand support. See this thread
. You may also need to search this forum for "plymouth graphics" and search Google for your particular VGA mode.