Simplified port requirements for Skype for Business Online

< My  Question is specifically for Skype for Business Enterprise - NOT O365 >

Besides the IP Address Ranges & Port Requirements for SfB- that we need to be sure they are whitelisted in our Firewall & Proxy Servers- What are the other requirements necessary to be considered?

I need a very clear concise answer, it is really appreciated. [ I feel like a loop in the links provided by Microsoft, they are just pointing one to another.]

Here are some thoughts & questions:

1) Is there any checklist/roadmap or action plan to check a full A-Z actions that should be taken?

Something like this: Actions to take to be sure skype for business online is functioning properly across your offices, branches, and organization:

1) check ports 

2) check IP ranges

3) FQDN and IP Address endpoints

...

2) For SfB, do we need to whitelist FQDNs also if we have already deployed and whitelisted IPV4, IPV6 ranges? or it is a redundant task?

3) For SfB, do we need to add PAC file in the proxy server to implement the principles?

                     [ same as what advised for Office 365:

Use our https://aka.ms/o365proxies to implement the principles below.

Bypass your proxy for all FQDN/CIDR paired and CIDR prefix only destinations, such as row 2 and 3 in portal and shared.

Bypass your proxy or remove inspection, authentication, reputation lookup services for any FQDNs marked required without a CIDR prefix, such as row 5 in portal and shared.

For any remaining optional FQDNs, wildcards, DNS, CDN, CRL, or other unpublished destinations requested by Office 365 services, ensure clients can access them over the Internet.] 

4) For SfB, do we need to a reach Office 365 worldwide endpoints? 

          [ same as what advised for Office 365:

[{"instance":"O365Worldwide","latest":"2018033000"},{"instance":"O365China","latest":"2018033000"},{"instance":"O365Germany","latest":"2018033000"},{"instance":"O365USGovDoD","latest":"2018033000"},{"instance":"O365USGovGCCHigh","latest":"2018033000"}

        ]

5) any other extra things should be considered?

Thank you in advance for your professional advice, time, and cooperation,

Ali