A good majority of the interactions of the heroic duos, Those Two Guys, and Those Two Bad Guys end up being described with some oddly chosen words. Presumably, Brian Jacques chose them unintentionally, but while the constant use of the word "mate" to describe a same-gender friend might be explainable, some uses clearly specifically meant mates in a rather sexual manner. Calling platonic friends "mate" is a very British thing, and non-Brits reading Redwall are often, justifiably, confused by it, made worse by the fact that in these books it's interspersed with "mate" in the sense of an animal's breeding partner.
In The Bellmaker, Rufe Brush has moments of this with Fatch and Durry equally. His personality also goes from "strong and silent" in an earlier book to timid, cautious, dependent, and generally very uke. He also names his sword after Fatch.
Not to mention from Mariel of Redwall Rufe is a badass stoic who completely ignores the, apparently gorgeous, squirrel Treerose's advances. But when his old friend Oak Tom comes to visit the Abbey he is laughing and wrestling around with him like they are little kids.
Clogg, apart from the "bitter ex" vibe he seems to have with Badrang, definitely seems to have something going on with Ballaw, who appears to be intentionally flirting with him. "D'you 'ear wot he called me? Sweet Cloggo. Ain't that 'andsome!" In the cartoon show, the searats give each other and the camera some very squicked looks when he says this. Getting Crap Past the Radar?
Outcast of Redwall features Sunflash the badger and Skarlath the hawk, who save each other's lives and go wandering together for several years. After Skarlath is shot and killed at the end of the book, Sunflash writes a sappy poem to Skarlath, including the line "O Skarlath, there was never one like you". Meanwhile, Sunflash's two otter friends Ruddle and Folrig live out in the middle of nowhere all by themselves, alternate between jokingly insulting each other and calling the other handsome, and take every opportunity to leap on each other and start wrestling/hugging. Also, they use a lot of nautical terms.
After the harewife reads Sunflash's poem to the leverets in the epilogue, she proceeds to tell them that he was "a great and wise badger with many unusual qualities." And just what doesthatmean?
Captain Snow and Squire Julian could possibly have got away with this if not for their species. Even when this troper was a kid, she looked at them and wondered if they have a beautiful pea-green boat. Since it's hard to believe Mr Jacques had never even heard of that poem, it really makes one wonder if he meant it.
Craklyn and Piknim have a bit of a Romantic Two-Girl Friendship vibe, particularly when Craklyn sings a lament over Piknim's grave, during which she actually calls her "my beloved". Also earlier on, when they sing alternate verses of a light-hearted love ballad at one another.
Mokug the hamster was, in his youth, kept as a personal slave by King Sarengo because the king "liked [his] golden fur". Squick.
Rinkul's announcement that he intends to recapture Tammo and Midge and "take 'em somewheres nice'n'quiet where I'll do that pair 'ard'n'slow afore dawnbreak" left this troper, at the age of fourteen, re-reading the whole page about four times to be sure it really had said what she thought it said, and then giggling uncontrollably. (Death by Shonen-Ai!)
In the scene where Tam and Doogy are imprisoned and taken out of their cell to see the King and Queen, there's a detailed description of them putting their kilts back on, so apparently they were sitting around naked. Well, they were in a cell, all by themselves, there wasn't much else to do ...
Surely, there was a way for Skipper of Otters to deal with Globby that didn't involve spanking him with an oven paddle.
According to one source on a forum, in the Russian version of The Taggerung, the translation made Eefera a girl, leading at least one Russian fan to believe (s)he and Vallug were a couple.