Is it known yet if there will be years 3 - 6 of 10 ESUs ? Was there ever a Software Assurance program of some sort for 10 ?
No. 4-6-year ESU license will probably allow manual installation of updates, in same way it did for Windows 7 with 4-6 years ESU license.
But Windows 7 need bypassesu 13f with mode server 2008 r2, for update automatically via windows update. So ask why technically mas don't unlock and don't change relations WU like make bypass ? Next question, why still older windows home editions still not supported to esu unlocked by mas? And last from where we should know if windows 10 home then for esu isn't placeholder, if mas don't work with home's editions?
Yes. But it doesn't need the Bypass for manual installation of updates, which was talked about here. Because it's not meant to? MAS deals with Activation and SKU-related tasks, not WU. IF Windows 10 WU will need any tricks to restore, there may be a new Bypass for it. What older versions? Windows 8 is dead. Windows 7, no, the ESU program explicitly excludes everything below Professional. Vista didn't get ESU; it needs BypassLH. Additionally, Vista is not completely updated by Server updates, only partially.
I have Windows 10 Education. I'd like to use TSforge to get ESU updates. I see in the instructions: TSforge <activation id>. Does it mean that I need to give it my Windows 10 activation id (which I don't know)?
Looks like an oversight, usually Administrators disable that page anyway when updates are centrally managed.
Can I use this just to activate ESU without touching the genuine Windows 10 license I already have activated? Is it the same as abbodi1406's ConsumerESU? meaning activating ESU with "Local account" is not possible anymore?
Yes, just choose to only activate ESU in the TSForge submenu. No, ConsumerESU is one year and Store-based, TSForge applies Commercial ESU, which is three years and license-based. Commercial ESU does not need an MS Account.