The Ferengi are slavers. The Bolian is probably property, captured on a raid similar to the one seen on Enterprise.It doesn't mean the Ferengi and the Bolians know each other in an official capacity.
Possible, but I think if they had a Bolian slave, they would have said something more like, 'I know sexy Bolian slave, I could ....."introduce" you'...
The statement seemed more to assume he knew a Bolian-as if he or the Ferengi frequently interacted with them enough to get to know them.
They find humans to be ugly and no doubt feel the same about races that look similar. No matter how often they see human looking aliens or females with clothes on their ingrained cultural bias will come into play and evoke a negative response.
Then you have to look at all the times the Ferengi appeared after their first appearance in The last Outpost.
Vash, negotiating over the Wormhole, Luaxane Troi, etc,they don't seem shocked by the appearence of human, or shocked that women wear clothes-even fall in love with them repeatedly.
The one with the Ferengi scientist.
They seemed to like Bajorans, Cardassians, Klingons, Vash, Troi, (humans) Kamala, etc most just humans with a different forehead .
I think the change was in part due to making the Ferengi part of the "community" so characters wouldn't have to keep saying "what? Who are the Ferengi?"