The only one eidolon below 1800 attack you have mentioned was only lilim and thats only lack 40 point to reach 1800. I think its safe to buy ikarus in shop because its stronger than tiamat both hp and attack. Quetzal maybe weaker but has high hp and it will be covered by at least 4% each bonus by using in sub eidolon if using hanuman support. Plus 10% extra status by having same element with the himes.