Asuka SR is a decent AoE for purple element. She isn't the best imo. Lilim SR has a higher def than attk. She is slower than Asuka, but she makes up for it by being a debuffer with her ultimate while still being an AoE hero. Asuka SR (event) is a tankier version of Asuka SR with lower speed. The upside to her is that she is a healer and an amper, buffing your team. She is great to have around when you use single attack heroes during boss grinding. Rinko SR is a single attack hero. She really shines in boss content. She does around 4k dmg with her ultimate at LR unbuffed.
Really depends on who you are looking to use. Asuka is good for general farming content since AoE helps with faster clears. Lilim is a great hero for cases in which you need to debuff the attack of the boss. Asuka (event) is a healer, which really helps in hard content when you don't have a lot of LR heroes. She also buffs attack. For instance, unbuffed attack is 400 for a normal hit. But when buffed, that is increased to around 600 per hit. That is a decent increase. And for Rinko. She is an incredible hero to use. She is highly desired for supports for boss farming players. Especially in this content with killing 44k hp Yukikaze, she does quite well. Not only that, by the time you get to end game, people recommend getting at least 1 healer, 1 tank, 1 buffer, 1 AoE, and 2 single target heroes.