Custom Sprites?

Is it possible to make a custom sprite sheet for Saria then repackage it into the original game for others to download?

Or would you need MMF2?

Yes, you can 
(without mmf2)
you use anime studio (or do it by hand which will take WAY  longer)
then you can ask nifflas/anyone else who has the full version to turn it into a sprite sheet!
you then put it in the zip with the level folder.
then put a readme telling the people to put the tilesheet into

Saira\Data\Sprites

then you just need to load it in objecs.ini 
there is probs an easier way

Huh.

*Ponders the possibility of getting Bobo sprites into the mix...

there is probs an easier way

Yes, there is.

Anime Studio, though a capable program, is certainly not the only alternative to hand-drawing the frames. It's equally easy to create complex sprites with large number of auto-created frames in Flash and Fireworks, for example. What's even more important is that the latter can lay out the frame sequence and save it as alpha-transparent PNG just like the ones that are used in Saira.

So bottom line is, if you already have an app that can do animation and export sprite sheets, don't feel like you're obligated to use Anime Studio or bother someone to export your AS files as sprites.

But he was asking how to get it ingame
i think?

then put a readme telling the people to put the tilesheet into

Saira\Data\Sprites

It isn't necessary to move the spritesheet to the Data folder, it's actually better to leave it inside the level folder together with the other sprites. The Saira sprites have been put there because they can be used of other levels.

Ah, yeah, a level should never modify the Data folder. If you want a sprite sheet global to your entire level, put it in a sub-folder of your world base folder (but begin the name with an underscore to tell the game not to think it is a star).