Вопрос: Как настроить ЧПУ на wordpress apache+nginx?

Лучший ответ: 1. Зачем вам Apache? Используйте Nginx + PHP-FPM, тогда для ЧПУ надо всего лишь одну строчку в конфиге Nginx.
2. Если все-таки Apache нужен, настраивайте ЧПУ в .htaccess. Nginx в данной связке всего лишь форвардит (проксирует) запросы на Apache, а их обработку производит последний.

Худший ответ: Как вам выше уже сказали, отказывайтесь от Apache и будет вам счастье. 
Вот вам конфиг и кеширование и много других полезностей.
Вот тут надо будет указать правильную версию вашего PHP.fastcgi_pass unix:/var/run/php5-fpm.sock;server {
	
	listen 80;
	set $root_path '/home/wordpress/www'; # default directory where the files will be stored and served from
	root $root_path;
	
	index index.php; # index defined to be served under directory
	server_name www.blog.com;
			
	set $skip_cache 0;

	# POST requests and urls with a query string should always go to PHP
	if ($request_method = POST) {
		set $skip_cache 1;
	}   
	if ($query_string != "") {
		set $skip_cache 1;
	}   
	
	# Don't cache uris containing the following segments
	if ($request_uri ~* "/wp-admin/|/xmlrpc.php|wp-.*.php|/feed/|index.php|sitemap(_index)?.xml") {
		set $skip_cache 1;
	}
	
	# Don't use the cache for logged in users or recent commenters
	if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_no_cache|wordpress_logged_in") {
		set $skip_cache 1;
	}
	
	location ~* \.(gif|jpg|jpeg|png|ico|bmp|wmv|3gp|avi|mpg|mpeg|mp4|flv|mp3|mid|js|css|woff|woff2|exe|eot|svg|ttf)$ {
		root $root_path;
		expires 14d;
		add_header Pragma public;
		add_header Cache-Control "public, must-revalidate, proxy-revalidate";
		access_log off;
		log_not_found off;
	}
	
	#    Common deny or internal locations, to help prevent access to areas of
	#    the site that should not be public
	location ~* wp-admin/includes { deny all; }
	location ~* wp-includes/theme-compat/ { deny all; }
	location ~* wp-includes/js/tinymce/langs/.*\.php { deny all; }
	location /wp-content/ { internal; }
	location /wp-includes/ { internal; }
	
	#    The next line protects the wp-config.php file from being accessed, but
	#    we need to be able to run the file for the initial site setup. Uncomment
	#    the next line after setup is completed and reload Nginx.
	location ~* wp-config.php { deny all; }

	#    Prevent any potentially-executable files in the uploads directory from
	#    being executed by forcing their MIME type to text/plain
	location ~* ^/wp-content/uploads/.*.(html|htm|shtml|php)$ {
		types { }
		default_type text/plain;
	}

	location / {
		try_files $uri $uri/ /index.php?q=$uri&$args;
	}

	error_page 404 /404.html;

	error_page 500 502 503 504 /50x.html;
		location = /50x.html {
		root /usr/share/nginx/www;
	}

	location ~ \.php$ {
		try_files $uri =404;

		fastcgi_pass unix:/var/run/php5-fpm.sock;
		fastcgi_index index.php;
		include fastcgi_params;

		fastcgi_split_path_info       ^(.+\.php)(/.+)$;
		fastcgi_param PATH_INFO       $fastcgi_path_info;
		fastcgi_param PATH_TRANSLATED $document_root$fastcgi_path_info;
		fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
		fastcgi_read_timeout    3600;

		fastcgi_cache_bypass $skip_cache;
		fastcgi_no_cache $skip_cache;

		fastcgi_cache WORDPRESS;
		fastcgi_cache_valid  5m;
	}
}
/etc/nginx/nginx.conf##
# Fastcgi Params
##
fastcgi_cache_path /var/run/nginx-cache levels=1:2 keys_zone=WORDPRESS:100m inactive=60m;
fastcgi_cache_key "$scheme$request_method$host$request_uri";
fastcgi_cache_use_stale error timeout invalid_header http_500;
fastcgi_ignore_headers Cache-Control Expires Set-Cookie;