Final Fantasy Hacktics

It looks like it is hard to do . I would like a Rosa FF4 Reina FF5 and Celes Battle green leo FF6 sprite

There is a specific section for sprite requests here: http://ffhacktics.com/smf/index.php?topic=1072.0

Thanks just wondering how hard is it to do ?

Depends on how complicated you get.  Starting from scratch is hard.  Basing your sprite on an existing one isn't that bad.  Minor edits to an existing sprite is actually pretty dang easy.

If you want a good sprite be ready to spend 10 hours on it; if you want a fully custom sprite learn pixel art for a year or so then be ready to sacrifice about 24 hours of your time pixel pushing and checking frames.