Almighty SEO gods, please help this frailing mortal with the right plugins. I'm so confused. lo

Hello, I would like to Maximize my WordPress to be as efficient and fast as possible. I want all the plugins I need and none I do not. I would like to stay with WPMU with everything I need. What Plugin regiment do you recommend for maximum SEO?

Please feel free to activate the plugins I need, deactivate and delete the ones I do not, or make a recommendation to which ones should be active and which ones I should delete.

I will be adding about 10 and no more than 20 items for sale in the website. Can you help me set this up with 20 dummy items I can replace once I am ready to launch?

Is this " Counsel Premium" theme a good one or should I switch it out?