In the optional Harem, best case scenario, It's safe to guess that there are pretty much character blocks from which you can pick only one, the office Group you can only date one from Candece, Julia, Kim,
From the sisters you can only pick one,
Sweet Olivia will probably never be in group situations,
have no clue how territorial Kimmy is, my guess is she will be OK with sharing,
that leaves Keyla the wild card, she either learns to share, or dies alone...
All of those are speculation on my part, obv.