you have to have pearl and ruby in the ds AT THE SAME TIME then you turn on pearl and when you choose start it should ask you if you want to migrate Pokemon then you must choose 6 Pokemon from the PC (you can use migration as much as you like)
migrate from ruby
Yes
migrate from sapphire or ruby
migrate it from Pokemon emerald ruby or sapphire
It is impossible to migrate from pearl to ruby.Once you migrated the Pokemon from ruby to pearl, you can't migrate it back ever again.
if you mean can you get Pokemon from pearl and diamond and trade them to ruby so you can get diamond and pearl Pokemon on ruby. then no you can not. but you can migrate ruby Pokemon. you put the Pokemon in ruby that you want to put on diamond or pearl in the PC. save it turn off. then go to diamond and migrate them. must be in ds at the same time. pal park.
you migrate lotad from Pokemon emerald and ruby, and migrate it in pal park.
migrate from Sapphire emerald or ruby
Yes, of course
migrate from ruby, sappahire, or emerald
migrate it from ruby, sappahire, or emerald.
no you have to migrate from emerald, sapphire, or ruby