[Need ADVICE] AliPlugin and SEO

Hello guys,

A few days ago I have started my journey with AliPlugin for WordPress. I started 3 narrow niche sites, imported the products with the plugin and after that, all I have done is to put analytics code. I am about to start 2 new niche sites tomorrow and 2 more each new week but before I continue I have few questions. I really like long answers with explanation but that is just me so I will put points on each question and I would love to see at least YES or NO:

1. Should I make more on-site optimisation?

2. Should I bother building backlinks on each of them?

3. Since all of them have blogs - should I make content SEO with the related niche also?

4. Should I make social networks accounts for each of the sites and automate them?

Any updates?

For all 4 is yes

No need for #2. Just download YOAST plugin in Wordpress for SEO. For social media, Twitter and Pinterest have good traffic.

Any updates?