I really love Lumine x Amber, but I can understand why people would ship Eula x Amber. Amber being there to support Eula and try to cheer her up while also defending her is really sweet. I would have probably shipped them if Lumine x Amber didn't exist lol
Also, I would ship Jean x Eula if i didn't find Jean x Lisa much more alluring. They remind me so much of Eli and Nozomi!