Once I did, I closed the channel afterwards. Should I?
I wanted you to try receiving a payment after making a few small purchases on Yalls since you should have gained incoming liquidity this way.
It's a multi-signature address sending 0.00299665 TBTC to one of my change addresses. Shouldn't there be an extra output with 0.0015 mBTC?
0.0015 mBTC is equal to 150 satoshis which is below the
dust limit. If an output is below the dust limit then it is added to the transaction fee automatically.