we don't support Monaca official, so we can't fully guide you on this. However your log output seems like that you have minSDK 14 defined, which is not enough for Wikitude SDK. Try to increase Android minSDK and try to rebuild. Also there seems to be a conflict in the manifest file, which you need to resolve:
Attribute application@label value=(Minimum Template(*)) from AndroidManifest.xml:5:83
is also present at :wikitudesdk::13:9 value=(@string/app_name)
uses-sdk:minSdkVersion 14 cannot be smaller than version 15 declared in library /private/tmp/monaca/578fd0b6fd1734c567e24ce2/android/skeleton/platforms/android/build/intermediates/exploded-aar/wikitudesdk/AndroidManifest.xml
Suggestion: use tools:overrideLibrary="com.wikitude.architectandlib" to force usage
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':processDebugManifest'.
> Manifest merger failed with multiple errors, see logs
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
Error code 1 for command: /private/tmp/monaca/578fd0b6fd1734c567e24ce2/android/skeleton/platforms/android/gradlew with args: cdvBuildDebug,-b,/private/tmp/monaca/578fd0b6fd1734c567e24ce2/android/skeleton/platforms/android/build.gradle,-Dorg.gradle.daemon=true
ERROR building one of the platforms: Error: /private/tmp/monaca/578fd0b6fd1734c567e24ce2/android/skeleton/platforms/android/cordova/build: Command failed with exit code 8
You may not have the required environment or OS to build this project
Error: /private/tmp/monaca/578fd0b6fd1734c567e24ce2/android/skeleton/platforms/android/cordova/build: Command failed with exit code 8
at ChildProcess.whenDone (/data/monaca_build_module/5.2/node_modules/cordova/node_modules/cordova-lib/src/cordova/superspawn.js:139:23)
at ChildProcess.emit (events.js:98:17)
at maybeClose (child_process.js:755:16)
at Process.ChildProcess._handle.onexit (child_process.js:822:5)