do all animé start from manga n so if it is succesful do most of the money go to the writer? (more similar questions inside) plzz answer

Well I'll answer as much as I can!
No not all animé start from manga. Sometimes there's manga after the anime, ou there won't be manga at all. animé can also start from visual novels, like (i think) Chaos;Head ou Steins;Gate!!

Not sure about the money, sorry..

And I guess it's personal preference whether toi want to do a manga ou anime. For manga toi sort of have plus freedom, of what toi want to draw ou write and making your own characters could be fun, but it can be hard to get it published...
For animé toi would most likely be drawing for other animes. So in their art styles and stuff (not too sure)

So yeah I hope I was sort of a bit of help! ^_^
(BTW toi should read the manga 'bakuman' talks a lot about creating manga, and it's entertaining!!)