is building bfly instead of the 2nd not good?
Butterfly gives +30 agi, +30 attack speed, evasion and damage to the main meepo, only the AGI benefits the other meepos. Eblade gives +40 AGI, +10 STR, +10 INT, which benefits all the meepos. Eblade gives more damage, attack speed, armor, and health to every meepo.
I can't imagine a scenario where you would ever want a butterfly on meepo. Things like Skadi, Eblade, hex, heart, and even manta are all significantly better on the hero. Meepo has item slot issues as is.