Need advice for starting a Managed Cloud Service for Small Businesses

Question

I hope this is in the right forum.  I have done a lot of research and searching but havent found anything that specifically answers, in total, what I am wanting to accomplish.  I live in a small town and want to start a Managed Cloud Services for
small to small-medium business in my area (2-30 users for each business).  I want to market this to have businesses replace their in-house server(s) to virtual ones I would host in a local Data Center with my own equipment that I would maintain.  I
am just starting off so I don't have any clients I do this for currently, but I get asked about this frequently.  I want to run a 2012 R2 Domain Controller and a Hyper-V 2012 R2 server.  The virtual servers I will host are going to be for AD, RDS,
FTP, and files.  Software examples that people are going to be using these virtual servers for are Quickbooks, Sage Accounting, Remote Desktop or RemoteApp, custom CRM or small database software, Office 2013, etc.  No Exchange currently but will
probably configure something for that in the future (maybe run 1-3 virtually for now if someone asks, but will only do it if the user base is fairly small ~under 10 users).  I only have 1 static IP to work with over a 100Mbps connection up and down.
For hardware, I am figuring something along the lines of this:
(1) 1U, single CPU w/2-4 cores, 8GB, 2x73GB SAS 10k RAID 1, Dual PSU, running Windows Server 2012 R2
Domain Controller
(1) 2U, 2x 8-core Xeon ~2.6Ghz, 80GB RAM, 8x600GB SAS 15k in Raid 10 for Storage (VHDX files, etc), RAID 1 small Basic drives (or USB stick) for OS, Dual PSU, Quad GB Nic which I can use for load balancing/teaming, Hyper-V
2012 R2
Hyper-V Virtual Server
(1) GB Unmanaged Network Switch & (1) Cisco 5510 Firewall
Most of my questions are about the best way to configure this.  I am planning on managing my Hyper-V from the physical Domain Controller server.  Each virtual server will have RDS & (possibly) AD services on a single server.
1) I want to replicate the physical Domain Controller.  Should I get another server or just virtualize the replica in Hyper-V?  I understand that if the Hyper-V goes down, so does my DC replica.
2) Should I use my Domain Controller to manage ALL users on each virtual Server, by creating separate Organizational Units for each business?
3) Should I setup my domain controller with Hyper-V management and then each Virtual Server I setup be a separate domain (Ex. mydomain.local, business1.local, business2.local, etc)?  Each one has no connection to any
other, completely seperate.  Or should I do subdomains (business1.mydomain.local).
4) What I have read is that Subdomains are a pain to manage with user rights, etc.  I want to keep each server complete separated from one another over a network connection, I suppose the VLan through Hyper-V options
do this?  I dont want wondering users to stumble upon another businesses files (I know they would probably be prompted with a login for that business/domain).
5) For each virtual server, I want to create and have an HTTP subdomain point to that server from my domain name. (Ex: business1.mydomain.com, business2.mydomain.com, etc.)  I want them to be able to have access to
only their RemoteApps or be able to type that address in their Remote Desktop program as the host name.  This would be for viewing the RemoteApp login page and RemoteApps for that business over HTTP/S through a browser.
6) If I do not have separate DC's in each virtual and my main DC manages each one, is their a way to connect up each companies RemoteApps using a single site that only shows what they are assigned to based upon their login?
(Ex. http://login.mydomain.com which then shows that user what they are assigned on their own virtual server)
7) Since each business will use the same ports for RemoteApp (443) & RDC (3389 unless I change it), how would I setup the subdomains to point to their correct server and not overlap for mess with any of the other servers
since its all over 1 static WAN IP for all servers.  Thats why I figured setting up IIS subdomains would solve this.
8) For backups or Hyper-V replication, is it better to have software that backs up the ENTIRE Hyper-V server (Acronis Advanced Backup for Hyper-V) as well as replication or just backups?  Or should I do separate file
backup on each virtual with a replica?  Can a replica be a slower server since its just a backup? (Ex. 1x 8 core, 80GB, 8x600GB 10k SAS)
9) For the servers that will be using FTP, can I again rely on the subdomains to determine which server to connect to on port 21 without changing each FTP servers ports?  I just want each business/person to type in
the subdomain for their business and it connect up to their assigned FTP directory over port 21.
10) If the physical DC manages DNS for all Virtual servers, can I forward sub domain requests to the proper virtual server so they connect to the correct RemoteApp screen etc.  Again all I have is 1 IP.
I hope all of these questions make sense.  I just want every business to be independent of each other on the Hyper-V, each on their own virtual server, all without changing default ports on each server, each server running RDS, (possibly) AD, (a few) FTP,
and all over a common single WAN IP.  Hoping subdomains (possibly managed through IIS on the physical DC) will redirect users to their appropriate virtual server.

Answer 1

If you really want to run your own multi-tenant service provider cloud, Microsoft has defined the whole setup needed.
They call it Infrastructure as a Service Product Line Architecture.  You can find the full documentation here -
http://blogs.technet.com/b/yuridiogenes/archive/2014/04/17/infrastructure-as-a-service-product-line-architecture.aspx
There are several different ways of configuring and installing it.  Here is a document I authored that provides step-by-step instructions for deploying into a Cisco UCS and EMC VSPEX environment -
http://www.cisco.com/c/dam/en/us/td/docs/unified_computing/ucs/UCS_CVDs/ucs_mspc_fasttrack40_phase1.pdf
This document contains the basic infrastructure required to manage a private cloud.  I will soon be publishing a document to add the Windows Azure Pack components onto the above configuration.  That is what would more easily provide a multi-tenant
experience with a Azure look and feel.  It is not Azure, but the Azure pack is a series of applications, some of which came from Azure, the provides Azure-like capabilities only in a service provider type of environment.
Whether you use my document or not (which has actually corrected errors found in the Microsoft documentation), you should take a look at it to see what it takes to put something like this up, if you are really serious about it.  It is not a small undertaking. 
It requires a lot of moving pieces to be coordinated.  Yes, my document is designed to scale to a large environment, but you need the components that are there.  No need re-inventing the wheel.  Microsoft's documentation is based on a lot of
real hands on experience of their consulting organization that has been doing this for customers for years.  This one is also know as Fast Track 4.  I've done 2 (2008 R2) and 3 (2012), also and it just keeps getting more complicated based on customer
demands and expectations.
Good luck!
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