there are a lot of things wrong with bitcoin unlimited but what you said is not it. any fork can lead to a split and 2 different coins. it has little to do with it being hard fork or soft fork and mostly it has to do with the amount of support they can get.
if any fork has the "overwhelming support" then there won't be any splits (like the previous hard fork that bitcoin had) and if it doesn't have that support then there will be a split like BIP148 which is a soft fork.
If am not wrong, the exact percentage was 80. So I guess it is overwhelming support. There are only few people who are still against the segwit so I don't think there will be 2 main coins after August 1.