E-commerce group/conglomerate

[Runn]

Hi All,

 

I am new; this is my first post. So much to learn, especially as I am not technical. Please, I have some questions and I'd appreciate any help.

 

I intend to build a site that will host a group of e-commerce sites focused on complementary markets. Example, an e-commerce site with marketplace for car spare parts, on the other side marketplace for auto mechanics and a corporate website about auto care tying them together. That's it basically.

 

My considerations:

1. Site architecture: corporate website is on  root domain, while each of the 2 marketplaces sits in separate subdomains accessible via linked tabs/buttons. I am wondering if anyone here has built something like that or thinks this is the right way to go (considering UX, SEO, etc)? Good or bad idea?
2. Website template: I plan to buy a complete website template for the corporate website and the car parts marketplace would run on Presta. I have seen some cute (Joomla, WordPress, HTML, etc) website templates and I wonder if there is a preferred CMS/platform template to mix with Presta in this way?
3. Blog/SEO: I have read a lot about impact of blogs and fresh content, so I am wondering how anyone here would do something like this: 3 different blogs in root and subdomains? Or, one blog in corporate site (maybe more reasonable)? In which case I'd just kill the blog on the Prestashop and use whatever blog comes with the corporate site template... But, how do you then achieve regular fresh content in all 3 (root & subs)?
4. Finally, does Google crawl member only sites (one of the subdomains might be member only)?

 

Thanks in advance for all your help.