Wasn't thinking about Connie.
Of the other tracks you listed:
Mello Souls - We Can Make It
Joseph Webster - My Love Is So Strong
Soul Inc - My Proposal
Keni Lewis - Not The Marrying Kind
I'd say that Mello Souls is just too obscure to find out who owns the rights. But, just a gut feeling, there might be a chance to secure the rights to Joseph Webster and Soul Inc.? Personally, I couldn't be bothered about K. Lewis comp'd. Never really liked it, way too fast and not that special (IMO!)