After the most recent presidential elections, multi-cornered fights became a thing of the past. People will now cast their votes either for PAP, or for the opposition party they feel has the best chances of winning, and not the opposition party whose ideology they agree with. Ideology is worthless unless you can first demonstrate your ability to win elections. Once you can win, you can start to talk more about your political ideology.
A split of opposition votes between the various low quality opposition parties was PAP's best winning strategy, but that was squandered on a powerless Tony Tan, while many others regretted voting for Jee Say and Kin Lian, and wished they voted for Tan Cheng Bock instead, who lost to Tony Tan by a whisker.
So, don't worry about multi-cornered fights. I dare say if WP contested in most of the wards for the coming GE, they should get the bulk of the opposition votes since of all the opposition parties, they seem to have the best chance of winning.