First, Speaker can vote in the event of a tie, so no, the Greens and NDP do have a majority.
Second, Greens made it abundantly clear that there will be an electoral reform. The disaccord was that Horgan wanted to have a referendum on it first and Weaver wanted to enforce it and then after two elections have a referendum to see if people want to keep it.
If the NDP vote yes today on the agreement, we will hear the details but given that Weaver was adamant about electoral reform as a condition of working together, I think it's safe to say that Liberals rejected the idea and the NDP agreed, even if the details of how it will be implemented remains to be seem.
The Liberals are the biggest benefactors of FPTP in BC where they constantly get more percentage of the seats than their popular vote.
I don't believe for a minute that CC would sit back for strategic reasons and allow this agreement to go on knowing that our electoral system is the biggest strength for her party.
More likely, she knew that Weaver is not going to compromise on the issue and her party's days of enjoying majority seats without majority votes are over either way, and she didn't want to be the one providing a helping hand in getting it done.
She could die a slow painful death or just pull the trigger. She chose wisely.