I have the following requirements:
1. Integrate C7 server into AD domain. I followed these instructions and it worked really well: https://www.linuxtechi.com/integrate...ive-directory/
2. Integrate samba on the same server such that domain users can connect to shares automatically using their windows credentials. The purpose is to allow connections without going through any password prompt.

I tried setting up samba as a domain member and as a stand alone server. As a member I couldn't get a clean testparm. As a stand alone I couldn't get it to recognize AD logins or even work as a wide open share (EG guesk ok = yes). Can anyone point me to a blog/url that explains how to do this?

I'm not sure I understand your Samba requirement, could you elaborate? What is a testparm? I think you are wanting a network share server, hosted by Centos7 with AD login.

I have integrated centos6/7 and rhel6/7 with AD. It's much much easier with 7 compared to 6 but it's not problem-free. I have found differences in experience on 7 machines simply by minor package versions. Very frustrating. For example, SSSD dynamic DNS not updating dns, or only updating its IPv6 IP. AD Join sending hostname in full capitals rather than actual case.

Now with AD login, depending on your config you can have people enter their user-IDs as "userID" or "userID@somedoma.in". Whatever your design has, you would need to ensure that samba is expecting the same.
To allow connections without a password prompt you need kerberos set up and working. You need the krb5 keytab (if I remembered correctly). May be you need to enable Samba for kerberos?

If nothing more, hope the above gives you a bit more info than you already had; to keep you moving forward.

Can you post your samba config? What version(s) of Windows are the clients?