At least for life as we know it it's very unlikely such can arise in methane seas. The cellular membrane is dependent on the interaction between water and lipids (fat) to even exist. If I remember my chemistry correctly methane does not have the "magnetic" property that water molecules have, which is super important for the chemistry of Earth life.

Water is weird chemistry-wise, and that's why there is so much focus on finding liquid water when it comes to xenobiology. If there actually is life on Titan, its chemistry must have to be radically different than our own, something we can't really envision.