I toured with a similar set up in a live dance music band, I have a Behringer 1202, I mad a balanced XLY "Y" Splitter and took my vocal mic into the 1202 with the other split going to the PA. I also took a line in from our Sequencer, Drum machine, sound modules and keyboard on stage sub mixer. There was also a line in from my Bass via a dedicated DI box.
I ran the ear phones from the headphone out of the 1202 and it was clean and loud. After trying many different ear phones pro and cheap, I settled on Koss Spark Plugs as they were not super expensive and had a good bass response. I have 2 sets with 1 set as spare, but have never blown them up. I have trodden on a pair though.
The rest of the band had a similar set up taking the line mix and having their own vocal, the live percussion player also had my bass going to his phones (he wore head phones as they stayed on when he jumped around).
We often played with no on stage monitors at all but when there was some we just got a little vocal and some drum machine for bottom end.
I don't understand why you are getting a lot of hiss unless the gain structure is completely wrong. Also be carful not to run the in ears too loud as you will destroy you're hearing. Started too loud and found when I got used to them I turned it down, it was a lot better.
Cheers
Alan.