Were Howard and Beverly Marvel's first interspecies couples?
I believe so as a human woman with an interdimensional duck Being in the comics with Beast and Carly on X-Men TAS (a blue furry cat-ape mutant with a human woman), Hezpibah and Corsair (human space pirate and furry alien cat-skunk lady) in X-Men TAS/Comics, Tigra (literal cat-woman with fur/tail and human man), Lilandra and Xavier (Alien bird woman who evolved from space birds and a mutant), Gamora and Starlord etc. are proof in Marvel you don't have to be the same species of Being to fall in love you know as Marvel isn't judgmental about odd romances.
Just imagine if Howard married Beverly with Nightcrawler as the priest with Marvel heroes at the wedding plus She-Hulk (whom is a friend of Bev and Howard) with Mary Jane Watson and Gwen as bridesmaids and Rocket/Deadpool as Bestmen? then later they go to Vegas for a honeymoon then he knocks her up as she ends up pregnant then later gave birth to an adorable little baby anthro duck Being baby which would be cute as Howard and Bev would be proud parents.
"Unicorn, mermaid, vampire,sorceress! No name you'd give her would surprise me i love whom i love"