Would anyone seriously be mad if Han just reappeared with some bullshit man hole cover explanation?
I know I wouldn't.
I mean how many cars did they roll out of in Furious 7 when they thought the predator blew up the car?
And Giselle disappeared into the darkness, so fuck it.
Bring em both back.
Hell, as far as I'm concerned they don't even need an explanation. Just have Han back on the crew and nobody ever mentions anything about his death.