The current strategy is to lean hard on the critical acclaim angle (IIRC they even tweeted a pic bragging that the film managed to score a "fresh" rating from Rotten Tomatoes, even though other recent films like the Purge Anarchy got better number scores than GB 2.0 did.
That will probably be the groundwork they lay as the film drops off massively in the next few weeks in terms of box office money. Especially since the film won't get a release in China, a place where even a turd like Warcraft can make big bank and become a huge hit.
That said, a greater problem lurks with the fact that stores are already discounting out the toys for the movie and the only ones that actually sold were the original male Ghostbusters, who were originally internet only exclusives, but who were given a retail release to pad out the GB 2.0 line.
Feig himself has stated that the film has to make huge bank in order to be deemed profitable by Sony and they don't have China or toy merch to fall back on. At this point, "critical darling" status is the only thing that they can fall back on to get a sequal made and even then, it will probably be years before it gets made due to the film damaging the Ghostbusters brand.
The closest they can get to salvaging shit is if they put out a Ghostbusters cartoon for the reboot, with whoever being in charge of the cartoon being instructed to heavily feature the old cast alongside the new cast and basically, giving them card blanch to salvage the reboot to the point of allowing them to outright ignore the movie and make it a direct sequel to the cartoon using the fan pitched "franchise" angle