Custom Block Templates - Description etc

I have been tweaking the way my category pages display by creating new block templates.

However as I wanted to include text in custom places, I don't use the default main category call which would bring up the long description to the category page in the default way.

If I am entering text on a category page via custom html blocks, will this be taken into account for SEO?

If I leave a product description empty, will my site still be indexed for what is physically on the page via the custom text entry via blocks?

With regards to the custom layout of a Product page via blocks, if I don't want to display the long description twice, can I use custom block html text in the template to enter text per product manually and then use the description tab to display the full description written in Edit Product?

A simple 'yes, all text you include will be accounted for' is all I need to know!