Unity detect wrong androidSDK version

I'm developing a multiplayer game with Unity 5 + PlayFab and I want to integrate Facebook plugins. However, after importing Facebook SDK package and I try to build my game to apk file, I get this error.

 Error: [Temp\StagingArea\AndroidManifest-main.xml:2, D:\Documents\[CPE403] Senior Project 2\ParticleShot 15 Mar2016 15.02\ParticleShot 20160316 14.26 Win-Lose\Temp\StagingArea\android-libraries\facebook-android-sdk-4.9.0\AndroidManifest.xml:3] Main manifest has <uses-sdk android:minSdkVersion='10'> but library uses minSdkVersion='15'
 

This still happen although I've already set the minimum API level in the setting to Android 4.0.3 (API Level 15).

And after I edited the AndroidManifest.xml manually, I get this error instead.

 CommandInvokationFailure: Unable to convert classes into dex format. See the Console for details.
 C:\Program Files\Java\jdk1.8.0_31\bin\java.exe -Xmx2048M -Dcom.android.sdkmanager.toolsdir="C:\Users\ThePriefy\AppData\Local\Android\android-sdk\tools" -Dfile.encoding=UTF8 -jar "C:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\sdktools.jar" -
 
 stderr[
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompat;
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompat$AccessibilityServiceInfoIcsImpl;
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompat$AccessibilityServiceInfoJellyBeanMr2;
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompat$AccessibilityServiceInfoStubImpl;
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompat$AccessibilityServiceInfoVersionImpl;
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompatIcs;
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompatJellyBeanMr2;
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/animation/AnimatorCompatHelper;
 Uncaught translation error: java.lang.IllegalArgumentException: already added: Landroid/support/v4/animation/AnimatorListenerCompat;
 ...

How can I solve this problem, thanks!