1 IRS does not allow FIFO on MLPs. You have an undivided interest in your investment. However, since KMR is an LLC and all gains are treateted as CG, I doubt that applies here and you should be ok.
2. Specific identification must be done and documented at time of sale, not after the fact. Fido makes this easy by letting you pick which shares you're selling when you place the order, most brokers do not.
3. Fractional shaes - Ameritrade does not let you keep fractional shares so every year I have 4 sales of KMR on my 1099. I just report 4 short term sales with basis and proceeds equal and therefore no gain. The IRS does match total sale proceeds from all 1099s received by you to what you report on Sched D, so its important that what you report on Sched D is at least what the 1099s show. Otherwise, you'll probably get one of those dreaded IRS letters. (I got a thick one last week but it was only forms for estimated payments for this year)