Lunarpages is a reseller for Tucows (domain registrar). Check the list of permitted domain TLDs (top level domains) on the account signup page on lunarpages.com and see if the one(s) you want can be registered "here" (.com and many others). .ca and .co.uk are not listed, but can be done manually. If you have domains that Tucows can't register, you'll have to leave them registered elsewhere. It is not required to move the domain registration to Lunarpages/Tucows in order to host here.

One domain will be your "primary" domain, and the other can be treated as an "add-on" (a separate domain and website under the same account). The second could instead be "parked" as an alias to the primary, if you want. The "add-on" will be seen to visitors as a separate, totally unrelated (to the "primary") site, and is implemented (internally) as a subdirectory (and subdomain) under your primary site.

If you can, and do want to, move your domain registrations to LP/Tucows, you can do so with support's help. There will be a small fee to transfer the domains. Be sure that you own the domains, and not the current registrar, and you have the ability to move them. They may be locked within a certain number of days of their renewal date. One domain can be then be held for free (as long as you have a hosting account), while the other you have to pay an annual fee.

I suppose you could, if your current domain registration is a separate thing from the hosting services. You can certainly build your main site at LP and then transfer the domain to LP and delete the main site from the old host, and then repeat the process for the add-on. Either domain could be your free one at LP. I'm pretty sure that you will have to go through the hassle of doing a domain transfer, even if Tucows is behind the scenes on both sides. Will your current registrar/host permit you to keep the domains with them, while pointing them over to LP's nameservers (and hosting them at LP)? I would expect them to charge less than they are now.

Perhaps I'm a bit confused by your wording. When you ask if you can "just change nameservers for both domain names", do you mean that you'd like to keep the domain names registered where they are now, and pointed to new hosting at LP? You'll have to talk to your current host as to whether they'll let you split your current account now (registration + hosting) and just use them as a registrar. The way they are set up, they may (or may not) want to act as just a registrar, in which case you may as well move the registrations over too. If you leave the domains registered at the old host, you will still have a free domain available from LP, whenever you choose to use it for a third site.

Are you asking to have the main site(s) kept at your other host, and just set up subdomains at LP? It's complicated, but I think it can be done. Why? If you own two domain names mysite1.com and mysite2.com, are you saying you just want to set up subd.mysite1.com and subd.mysite2.com? I'm not sure I understand what you're trying to do.

Yes, you can create an unlimited number of subdomains for your main or primary domain name you transfer over here.  At this time we do not support subdomains for addon domains, due to the way cPanel handles the addon domain/subdomain relationship.  Hope that helps!

You would need to re-create the e-mail addresses on our side once you got the domain name moved over via your control panel. 

If you don't get a 404 what do you get?  You might give us a working example and we would be happy to look or if you would rather keep it private then you can e-mail the situation over to support@lunarpages.com and I am sure they would be happy to check it out too.

What script or service do you have running the backend of the web site and design?  Also you might check your .htaccess file to see if there is any special code in there that is redirecting and errors back to the index.