I'm not experienced in most areas of interest, so I won't comment.

However, I was faced with the same problem you mentioned in (4). Two months ago I was going home for winter break (30 days) so I bought an Oasis watering system. It cost me $90, but it made my grow possible. Something like this might help you out.
(I have no further use for the system, so I'm selling it now... http://boards.cannabis.com/showthread.php?t=52030 )

You also might be able to find something like this at a local gardening or hydroponics store. Good luck with everything.

joe.