First of all, I would recommend performing repartitioning, most preferably using GUI solution (via package Backupmenu, it's mass-storage read & write mode, and linux PC - be it true linuxbox, or any other just booted with linux liveCD). The earlier You do it, the less concern if You manage to break something.

If You're planning to be "serious" Easy Debian user (or want, for example, Chromium or LibreOffice running from Maemo, via Easy Debian), You should add 4th. partition - 3GB should be sufficient in most cases - that You will use as native partition for Debian chroot, instead of using image file on vfat (performance reasons). I would recommend using ext4 as it's filesystem (it adds kernel-power to list of installed packages before starting - alongside backupmenu - as stock kernel doesn't have ext4 support).

If You're power/advanced user of GNU/Linux overall (not afraid of modifying some things latter, mess using terminal etc), You may consider reformatting Your home (/dev/mmcblk0p2) to ext4, while, of course, also increasing it's size (in cost of MyDocs - aka /dev/mmcblk0p1 - partition, as it was while creating dedicated partition for ED). Consider this advice only, if You're knowledgeble, and understand how to modify boot scripts related to /home/ (to make them consider it ext4), or You can search & read wiki/forum threads with understanding (I learned about it by reading, decided to perform, got sure that I understand WTF, and it went flawlessly - before that, I had no idea how it works).

If You're planning to use swap on microSD (which is only possible sane approach, unless You like decreasing performance without any gain), You may consider resizing /dev/mmcblk0p3 (SWAP) partition, to something like 100MB - You won't use it at all, so it's only failsafe reserve. No need for it to occupy 768 MB.

Then, You can happily proceed to joyful and straightforward process of installing CSSU, kernel-power (if You haven't decided to use filesystem different than default ext3, that require having kernel-power before repartitioning), Easy Debian (remember to mount it's image file somewhere, and cp -a it's content to Your dedicated partition, then modify ED scripts to use it from partition, instead of filesystem image), and whatever package You feel fancy.

And, if You haven't started screaming and running after reading this - it's all quite well documented, logical and stable, so don't get confused by how complicated it sounds, written in short manner here in my post

/Estel