The MST200 has a built in antenna with 13dBi of gain. The ANT-2x2-5314 is similar, with 14dBi but with slight different beamwidths.
The ANT-2x2-5314 only provides two antenna leads, while the AP274 has three (per band). If one of the antenna connectors is left unused, it should be connected to a terminator.
Distance should be fine, but for any outdoor deployment the installation options and physical environment play a significant role.