Being a big fan of Paul Walker (since Pleasantville & Meet the Deedles) and of Fast & Furious... no it would not be morbid or in poor taste if they found a way to include him/his like-ness into the new attraction. Afterall, he is & always has been an integral part of the franchise. It'd be a fitting tribute to the man that helped make this franchise what it is today.
and come on,... would it really be any different from Michael Jackson & Tupac performing onstage long after their deaths? No, no it wouldn't.