Magento – Foreign key fields auto increments conflicts in magento 2 install schema

I just converted the Magento 1(created by Ultimate Module Creator) module Install script for the new magento 2 Install-Schema script, here I got some trouble.

The referencing fields also has the auto increment. Please look at the below code that should make some sense.

$table = $installer->getConnection()
        ->newTable($installer->getTable('vendor_blog_blog_comment'))
        ->addColumn('comment_id', \Magento\Framework\Db\Ddl\Table::TYPE_INTEGER, null, [
                'identity'  => true,
                'nullable'  => false,
                'primary'   => true,
            ], 'Blog Comment ID')
        ->addColumn('blog_id', \Magento\Framework\Db\Ddl\Table::TYPE_INTEGER, null, [
                'identity'  => true,
                'nullable'  => false,
                'primary'   => true,
            ], 'Blog ID')
        ->addColumn('title', \Magento\Framework\Db\Ddl\Table::TYPE_TEXT, 255, [
                'nullable'  => false,
            ], 'Comment Title')
        ->addColumn('comment', \Magento\Framework\Db\Ddl\Table::TYPE_TEXT, '64k', [
                'nullable'  => false,
            ], 'Comment')
        ->addColumn('status', \Magento\Framework\Db\Ddl\Table::TYPE_SMALLINT, null, [
                'nullable'  => false,
            ], 'Comment status')
        ->addColumn('customer_id', \Magento\Framework\Db\Ddl\Table::TYPE_INTEGER, null, [
                'identity' => true, 
                'unsigned' => true, 
                'nullable' => false, 
                'primary' => true
            ], 'Customer id')
        ->addColumn('name', \Magento\Framework\Db\Ddl\Table::TYPE_TEXT, 255, [
                'nullable'  => false,
            ], 'Customer name')
        ->addColumn('email', \Magento\Framework\Db\Ddl\Table::TYPE_TEXT, 255, [
                'nullable'  => false,
            ], 'Customer email')
        ->addColumn('updated_at', \Magento\Framework\Db\Ddl\Table::TYPE_TIMESTAMP, null, [], 'Blog Comment Modification Time')
        ->addColumn('created_at', \Magento\Framework\Db\Ddl\Table::TYPE_TIMESTAMP, null, [], 'Blog Comment Creation Time')
        ->addForeignKey(
            $installer->getFkName(
                'vendor_blog_blog_comment',
                'blog_id',
                'vendor_blog_blog',
                'entity_id'
            ),
            'blog_id', $installer->getTable('vendor_blog_blog'), 'entity_id',
            \Magento\Framework\Db\Ddl\Table::ACTION_CASCADE, \Magento\Framework\Db\Ddl\Table::ACTION_CASCADE)
        ->addForeignKey(
            $installer->getFkName(
                'vendor_blog_blog_comment',
                'customer_id',
                'customer_entity',
                'entity_id'
            ),
            'customer_id', $installer->getTable('customer_entity'), 'entity_id',
            \Magento\Framework\Db\Ddl\Table::ACTION_SET_NULL, \Magento\Framework\Db\Ddl\Table::ACTION_CASCADE);

I just need a way to sort out. If I am wrong somewhere please figure it out.