[Samba] A set of questions before building a new server

[Robert Moskowitz]

I have a Samba server here with 4 users and 4 XP systems.  Kind of 
small, but it does the job.  It is running as a PDC with roaming 
profiles.  I should note that I left professionally supporting Windows 
networking around the time XP came out, so I have maintained an NTDomain 
through a number of incarnations (NT, Win2000, Samba2/3) and use of 
someone elses packaging.  This time I want to use as direct-to-Samba as 
I can.  All I want with this server is to be a Samba server to Windows 
(and maybe Linux) machines.

I have new hardware, an armv7 board that I can run either Redsleeve 6 
(Centos 6 arm port) that has Samba3 or Fedora 21 that has Samba4. I have 
new XP systems (updated with 'SP4' and right now standalone) ready to 
use this server.  I will have to migrate 2 of the old systems.  The new 
server can be on a new subnet with a new rfc1918 network address.  I 
will also be serving gobal/static IPv6 addresses on this new network.  
At some point I may actually have a new Windows OS system, but there is 
no pressure here to do that.  My family is so far content with Office 2003!

So a set of questions come up:

Do I migrate from NTDomain to AD, or stay with NTDomain for a few more 
years?  Actually can be a total fresh build of AD.
Does AD require Samba 4?  I have looked at the Wiki, and have not seen 
this clearly stated, but that is probably my reading challenges.
Does AD support roaming profiles?
I like that AD has the LDAP built in.  But do I still need an LDAP admin 
tool for AD?
If I stay with NTDomain, what LDAP tool to use?

As I start building, then rebuilding the new server, I know I will have 
more questions.  Hopefully most will be on the Wiki, and I will be able 
to find them.

thank you
Now back to reading more on the Wiki and elsewhere