If I change all the names in the classes and the Manifest, but leave the original one in build.gradle, will this cause any problems when sending an update?
Another question asked if there was a way to change the part in the URL, but I know that's not possible. I mean changing what appears in the manifest and the classes.
No, Google Store cares about two things the first one is the module.gradle, it will check if the code version changed. google store detects update by the code version, should be higher than the current one otherwise it will reject your update.
the second thing which google cares about is it the key store, since google will not accept the update unless you use the same key store which you used at the first one
