Can you trade pokemon from blue version to emerald?

Answer 1

no - and you already know this, because you have already tried

red, blue, and yellow had errors in them. mostly with the item duplication

gold, silver, and crystal had massive errors. besides the pokemon/item duplication trick, the EV layouts were dispersed so that you can get up to 1530 Ev points, instead of the cap of 510 that was introduced in ruby, sapphire, fire and leaf - and later pulled to emerald

plus, you have to consider that if you WERE able to trade, you need to have trades that could exist in blue. there is no way that you could have a steelix with the move iron tail in your blue version, for example.

Answer 2

No, Blue version is incompatible with Emerald, Blue can only be traded with Yellow, Red, Gold, Silver and Crystal.

However, fire Red, Leaf Green, Ruby, Sapphire, Ermeald and the upcoming Diamond and Pearl can be traded.