Some other Heyers: The Spanish Bride fictionalises the diary of an officer in Wellington's army and his marriage and love to an impoverished Spanish aristocratic young lady who follows the drum with him. I think it portrays the life in the army extremely well and I simply like Juanita and can grin at Harry's realistic thoughtlessness - and there's a large helping of amour fou in between both of them. The side characters in the army are extremely well developed.

You're missing "the stoic hero whom everyone underestimates and who saves the day" - my favourite of those is The Unknown Ajax, because it's the guy basically having a great tolerance and sense of humour and deciding to play the role his family means him to play to the utmost. Since it doesn't end in schadenfreude, it's a fun bit. Also a great dramatic con-scheme at the end. Another one in that vein, a bit more sedate, is The Toll-Gate.