DNS, Fully or not, and email n webmail

Greetings everybody;
My first post here, I will try to keep it short, coherent and proper terminology. In my ignorance, my questions here are tied together, coz I think the answers may be; apologies in advance.
I will be referring to the Control Panel below:

  1. Concerning two of my registered domains (w DH), listed under “Managed Domains,” column ‘Web Hosting’ it says DNS only; column ‘Email’ it says one 0 (zero) address, the other with 1 address.
    When I look under “Registrations,” I see one of the above domains, under the ‘Hosting’ column, as ‘Fully.’ All the others are ‘Add.’ When I check on that "fully’ domain, DH says it is not hosted, would you like to add, etc.
    Is this Fully Hosting in error?
    I have no reg.domains hosted and ‘working’ yet with DH or others (I’ve been lax).
    But can all domains could be “turned on” to DNS, without hosting, and if so what changes occur to them in DH?

  2. Related to (1) above, under “Manage Email,” DH says I have no hosting plans. Under “Webmail,” I have one domain (of the two above), with webmail enabled; the ‘Fully hosted’ is not enabled, but listed.
    So what are differences bwt webmail and email? I understand (famous last words) that the mail is hosted somewhere, the one I have now as DNS webmail seems to function, (but I havent figured it out yet). Can webmail exist for each domain, without the ‘fully’ hosting?

  3. So related to (2), can a “in progress” type of web page be created for each domain, with a webmail? Or does each reg.domain need be hosted before a “in progress” page can be created?

Thanks for your help (and patience).

I find most of my answers are hiding under Add Hosting, in Manage Domains, oops. I had assumed it was only a Fully hosting option.
Just fyi