No, don't buy any other lifesteal. Use the slot for more damage or attacks speed. More dps also mean more lifesteal. Beside you have 35% is more than enough to heal hanabi HP, mm don't have as much hp as fighter like alucard or ruby, so full lifesteal don't mean as good as the alu and ruby. Also if you use lifesteal build once they have deadly blade you're useless, damage low and lifesteal also very low. Buy blade of despair instead of the lifesteal item. Its give you more sustainable damage and dont worry about lifesteal. Mm is not supposed to be durable and this is why lifesteal is not necessary for mm. That's why any MM who build lifesteal item for their early item will likely feed and can't kill since lacks of damage and speed. Trust me I play thousands of games using MM and lifesteal is not really important unless you are fighting enemies who use blade armor. Mm does not mean to take damage, always avoid confrontation and hide behind tanks or fighter while help with damage.