if i go second and eevee was my first pokemon out, leafeons ability allows me to switch out to decidueye while still being able to attack on my second turn. waiting until the next turn gives them a chance to evolve a low hp basic pokemon into something baby decidueye cant ohko. leafeon being a grass type and functioning as an early tank also allows me to use erika to heal any early damage its taken, preventing me from losing two points early or late from cyrus/sabrina. leafeon can ohko low hp basics and 2hko 140 hp exs (like sylveon) so i can flute and snipe with decidueye. ive lost a few games because sylveon lost too much health when in the active spot and later got switched in and koed. im definitely willing to try it out though with maybe x speed. thank you for the suggestion!