1- Do you suggest deleting the Avastemupdate.exe? Is that ok for Avast to run?
No, I'm certainly not suggesting it - I'm saying it's ridiculous because bigger changes are delivered via virus definition updates (that you, at least most likely, update automatically anyway) than this tool would. But if you, for some reason, feel the urge to disable it, then yes, it's OK to remove/disable the scheduled task, it won't affect avast's normal functionality in any way.
2- If deleted, it will not make calls?
Not sure what you mean... if it's not started, then of course it wouldn't make any calls.
If you're asking whether avast! is using other means to start the executable then the Task Scheduler, then no. The whole point of this tool is to be standalone, independent on the rest of avast! in any way - so that it would be able to run even if the rest of avast! wouldn't load.
So if avast! itself wanted to make similar calls, it would do that directly, without using AvastEmUpdate.exe.