Difference of opinion, but to me, one kiss between women does not a "lesbian relationship" make. By that logic, Ashley and Lily would be in a "lesbian relationship" because they kissed during the dildo spin game, and Quinn and Camila would be in a "lesbian relationship" because they kissed when jerking the MC off in ep 1.
A drunken kiss between two women, whether they be friends or strangers, is just a drunken kiss between two women. Anyone is capable of it regardless of their sexual proclivities, and that includes Bella and Jill.