A: Yes. Internally, Microsoft codes the LTSC branch as "EnterpriseS" (S for Server SAC? Actually it's for "Stable"). For IoT Entry, you might see CLIENTENTERPRISE_VOL_OEM – that’s correct.
: Official ISOs are exclusively distributed through the Microsoft Volume Licensing Service Center (VLSC) or Visual Studio Subscriptions (MSDN). A: Yes
Guide to Windows 10 IoT Enterprise 2019 LTSC Entry: Verified ISO Downloads and Licensing A: Yes. Internally