sww, yes and no. I saw her yesterday. Yesterday I saw her. English allows these two as I understnad. In Russian you can say: Her yesterday saw I: "speaking about her, the guy who saw her yesterday was me" It changes meaning. But not ALL the possible word orders are common or possible. Some are just nonsense. Some don't change meanign much, but are not common.

it is possible , but take as rule , you should put first the word you are accenting , Я вчера только тебе это говорил ( it was just yesterday that i said something to you ( may be you already forgot the information ) . Я только тебе это вчера говорил - I was just you i was talking to yesterday ( may be others were not allowed to know i was talking about ) Я только говорил это тебе вчера ( i was just saying it to you yesterday ( may be i hadn't plan to do what i was talking about ) , something like that . In other cases the order doesn't express the meaning so strictly .Voice intonation has a lot to do with accenting meaning as well .

Yes, there is no word order. Instead of it we use intonation and logical stress.

The order of words is not so much for the meaning like for shade of meaning.

Yes its true. You can use any word order you like. Just you have to use the right endings of the words.