they are using bukkit ,spigot ,forge 1.8
forge server for 1.7.10 need the client to have forge
forge server for 1.8 dont need the client to have forge but if you have common mods like buildcraft then you need the client to have forge
[11:11:08] [main/TRACE] [FML/]: Adding CodeChickenCore-1.8-1.0.5.34-universal.jar to the list of known coremods, it will not be examined again
that is 1.8 get 1.7.10
Java HotSpot 64-Bit Server VM warning: Exception java.lang.OutOfMemoryError occurred dispatching signal Unknown Signal to handler- the VM may need to be forcibly terminated
give it more Memory