multiple google tracking codes on one web site

Yes you can, but you have to use a certain one.

https://support.google.com/analytics/answer/1032400?hl=en

adding new properties
https://marketingplatform.google.com/home/accounts?authuser=0

Testing web sites for speed, security, seo etc.

web site speed test
https://tools.pingdom.com

SEO reports

https://seomator.com/free-seo-audit-tool not a bad free tool

meta tag analysis, see meta tags in a site
https://www.seocentro.com/tools/search-engines/metatag-analyzer.html

https://www.woorank.com/


check h1 tags on a web site

https://www.seoreviewtools.com/html-headings-checker/

cloudflare

https://support.cloudflare.com/hc/en-us/articles/201897700-Step-4-Recommended-First-Steps-for-all-Cloudflare-users

naked domains vs. www domains

https://www.jackkinsella.ie/articles/www-vs-naked-domain

web site speed tests 2018

https://tools.pingdom.com/

Liferay google analytics

Liferay wants you to use gtag

https://support.google.com/analytics/answer/7476333