"Winane basic AI method" is for old MUGEN version like the winmugen to make it get to know "I am A.I." sooner and better, it has nothing to do with the A.I. itself. In your Rosalina case, she is for MUGEN1.1 only so using the MUGEN1.0/1.1 AILevel Trigger is more than "good enough" to activate Rosalina's A.I. at the right time.
In my humble opinion, there is no "advanced A.I." in MUGEN. It is because that, to be able to make MUGEN character A.I., it already takes almost all of your MUGEN knowledge and experience (at least the Triggers part and some MUGEN variable & random setting state controllers) to do so.
There are only "levels of computer reflex" you make with the MUGEN ChangeState state controller (and others like VarSet, VarAdd, VelSet, VelAdd,...etc.). The only "advanced" part I can merely say is, making A.I. only states that can never by used by a human player, not just by using ChangeState state controller all the way.......
Let me give you some examples.
1) Level 0 A.I. - Kung Fu Man: just make his moves randomly without instruction, most of the times he loves to perform Smash Kung Fu Upper followed by a Fast Kung Fu Palm
2) Level predictable A.I. - my MUGEN stuff
most of my MUGEN A.I. is predictable if you get the pattern........
3) Level a-bit-human-like A.I. - Ryu by PotS: in my opinion his Ryu has MUGEN A.I. that is a bit close to a human player's
4) Level accurate A.I. - SF3.3 Gill by GM: accurate source game A.I. which can be quite challenging
5) Level brutal A.I. - MUGEN stuff by ikaruga and Kamekaze: mostly their MUGEN A.I. has super-human reflex that almost counters every move of yours and that rarely gives a you a breathing space at all
6) Level impossible A.I. - all those used in MUGEN Watch Mode only matches, usually extremely over-powered and unfair
Thus, you may want to try some other MUGEN characters' A.I. and study what kinds of MUGEN state controllers and Triggers the authors use and then make your own MUGEN A.I. (probably with a lot of trial-&-error attempts) for your Rosalina and/or other MUGEN goods of yours.
Last but not least, I suggest you go to read some posts in this MFG topic: http://mugenguild.com/forum/topics/how-do-you-make-ai-patches-147932.0.html
[EDIT]: oh there is a good MUGEN A.I. tutorial at the official Elecbyte web site here: http://elecbyte.com/wiki/index.php/AI but it is currently off-line.......