category 2: makes sense, doesn't compel me. i get it. i do. prefect lucius took snape under his wing. they were death eaters together. they stayed friends for years after the war (except not actually because snape was secretly working against lucius). their power dynamic shifted because although lucius was a wealthy pureblood and snape was a penniless halfblood voldemort favored snape...especially after his return when lucius fell out of favor with him. there's tons of stuff that that should make it compelling. but they both are just don't fit together somehow and are so much more interesting with other people. I just can't bring myself to care.
YES. category 1: makes sense, compels me. unpopular opinion but I am SO here for this ship. however, i'm here for it in a toxic heathcliff and catherine type way. give me feral snape and equally feral lily. snape likes inventing spells and exploring dark magic and so does lily. harry doesn't just survive the killing curse due to a lucky sacrifice. he survives due to a willing blood offering and some frankly desperate, dangerous and downright insane blood magic on lily's part. snape is the only one who ever really sees her. let them be vicious and obsessed and rough around the edges. give me the disaster snily ship i crave.
don't kill me but personally for me this is a category 4: doesn't make sense, doesn't compel me. I feel like this ship works more in fanon with different personalities for the characters than in canon. luna and ginny were never that close. ginny is the first one to say luna is weird and call her looney. and yeah she defends luna once in book 6 but like. we never really see them hanging out and they seem to be different sorts of ppl. I can see how it could work - if we imagine ginny as an outcast post book 2 experiences and have her end up bonding with luna over that. i don't hate it or anything. im just...indifferent;.
send me a ship and I'll tell you which of these categories it falls into