Almost certainly not, because it is extremely likely that the liability to pay service charges (and probably a small amount of rent as well) arises under a long lease.
They won’t be “owners” in the HB sense because that definition only applies to freeholders. But their service charges and ground rent are still excluded if the lease was originally for 21+ years. Instead, they can get IS/JSA/PC depending on their age and job market status.
There is an exception to the general long lease exclusion for shared ownetrship leases, where the occupier gradually acquires a percentage stake. If any of your claimants have shared ownership leases, they can claim HB for the service charges and ground rent, unless they have already claimed IS/JSA/PC for the same costs (and vice versa)