How do trades work in Pokemon Ranch?

Hayley was offering a Kingtra for the BBS trade for a Hippomatos. Shannon didn't have it in her pokedex and so she wasn't able to transfer it to Pokemon Ranch. As for me, I transferred it and I am confused about how come neither of us got a Kingdra from her. Can you transfer pokemon that you gotten from her to your game and to fill out that pokedex?