I don’t file music by genre, since any decent media manager/player will allow you to browse by the genre metadata tags.
I’d recommend a media storage that reflects your physical collection. I use a very simple four-level hierarchy:
<source>/<album artist>/<album>/<track>
Where <source> is where it came from (my ripped CDs, purchased downloads, free downloads, etc). This is an optional level of hierarchy.
Once you have imported your music into a library, you can browse by whatever metadata fields you like, including the physical file structure (‘By Folder’). That is, assuming your metadata tags are correct and complete…
I’d also recommend that all track filenames are prefixed with a leading-zero track number, which will give you the correct track order in even the most basic of media players (using alphanumeric sort order). e.g.
01 track one.ext
02 track two.ext
...
10 track ten.ext
Then you don’t want (or need) the iTunes server, assuming the tablet is also Android.
BubbleUPnP handles DLNA metadata very well, including forcing numeric search order for albums.
You might benefit from reading how to setup and optimise the Twonky media server:
