The New Exchange Reaches RTM!

Can anyone answer my questions #3-5  and new question 6 below?  

Let me expand a bit on my original question #4.  Now that the server editions for server 2012 have changed what are the specific requirements for high availability in Exchange 2013?  In Exchange 2010 I believe it was required to have Server Enterprise Edition to have HA for the CAS role right?  Now we do not have the same roles nor do we have an Enterprise Edition of the OS.  Will we require the Datacenter Edition?  Will Standard Edition work?  I have to make some licensing decisions ASAP so an answer would be appreciated.

We have several customer scenarios where for various reasons we are eager to move.  This mostly revolves around hardware deployment issues.  (eg - We know we have to replace servers now and would like to minimize the number of migrations, upgrades, redeployments, need to additional hardware, etc.)

Questions:

3)  If "co-existence" is out of the question, is a complete "migration" from an existing XS2K10 to XS2K13 RTM possible?  Is we accept downtime to get a migration done can we actually do it or is migration also dependent on "co-existence"?  Is this documented anywhere?

4)  Is there any specific information on deployment of diversity for all roles (Both in single site and over a WAN)?  Load balancer requirements etc?

Let me expand a bit on my original question #4.  Now that the server editions for server 2012 have changed what are the specific requirements for high availability in Exchange 2013?  In Exchange 2010 I believe it was required to have Server Enterprise Edition to have HA for the CAS role right?  Now we do not have the same roles nor do we have an Enterprise Edition of the OS.  Will we require the Datacenter Edition?  Will Standard Edition work?  I have to make some licensing decisions ASAP so an answer would be appreciated.

5)  I am interested in hearing anyone's experienceknowledge about supported Microsoft or third-party apps for backup (eg Symantec BackupExec, CA Arcserve), Antivirus (eg symantec, TrendMicro, others), and antispam (eg GFI Mailessentials), fax integration (eg GFI FaxMaker).  As usual these are probably the blocking issues fro actual production.

6) Let me add a question 6.  What exactly would I need in the way of load balancer(s) in various scenarios.  It sued to be that the general consensus was that you had to get a hardware load balancer becuase the windows load balancing service was not a good solution.  How is taht in Exchange 2013 now?  What woudl be required to support HA in a single site environment?  What would be required to support full HA in a two-site (geographically diverse) environment?