I made Chrom a Cavalier, though. Think of going through Paladin to Great Lord for him. Should make him a bit more sturdy. I'm thinking I may be over-complicating things. As suggested by me running low on Seconds Seals before they become available to buy.Just make Lucina a Great Lord, is not like you need galeforce for the main game. As a great lord she should be able to finish with no much help other than a pair up. Same for Chrom. Also Myrmidon Sully for astra. Then go back to whatever class she was.