Ceci est an answer to your first question: See which Microsoft compte the license is linked to.
Il n'y a pas de direct way to scomment which compte a digital license is bound to. The compte périphérique list du Microsoft compte cannot be trusted: Si je add another (non admin) utilisateur avec a Microsoft compte to my machine, the name du ordinateur sera added dans le périphérique list du nouveau compte, too. Certainly, the digital license of my ordinateur is encore bound to my (admin) compte and not vers le nouveau utilisateur.
Therfore vous devez vérifiez le list of digital licenses in every Microsoft compte you own.
The seulement method Je sais to list digital licenses bound to a Microsoft compte is to try to transfer them to a nouveau, "unknown" matériel. "Unknown" means, that on this matériel Windows 10 has not been installé avant. "Try" means just to begdans le transfer processus until the last step and not to finish the activation processus.
This nouveau, "unknown" matériel can be a real matériel (nouveau mainboard) or a virtual matériel (e.g. VMware machine virtuelle). C'est important to notez que the fingerprint of this matériel shall not exist dans le database of Micrsoft's activation servers. Otherwise the matériel sera activated automatiquement and you ne va pas get a chance to transfer a different digital license to it parce que it déjà has a digital license. The transfer processus ne va pas get offered.
My method for Windows 10 b1607 is as follows:
Créez un nouveau machine virtuelle (VM)
Installer Windows 10 sans any clé de produit (the edition ne matter, Home or Pro, x86 or x64)
Essayez to activate the VM
Entrez the windows activation dialog where it is possible to transfer your digital licenses to this VM ("Troubleshoot", "I changed matériel on this périphérique récemment")
Entrez your Microsoft compte credentials du compte which you want to check
Maintenant you get a list ("Reactivate Windows", "Sélectionnez this périphérique from below") of périphériques which are bound to your Microsoft compte and which have a digital license and which are dans le same "périphérique class" as your current périphérique (the VM). This périphérique list is the first part du whole list of digital licenses du compte. "Périphérique classes" are e. g. laptops, standalone PCs or machine virtuelles. In my opinion machine virtuelles are separated in different périphérique classes, too (VMware, Oracle, etc.)
To see the second part du list of your digital licenses vous devez list all périphériques which ne pas match the current VM, i.e. which belong to a different périphérique class. Click sur le link en bas of this page: "See other périphériques linked to your Microsoft compte". Maintenant you get the second part du list of your digital licenses which belong to périphériques that cannot be transferred ("Périphérique tapez ne match", Edition ne match")
This whole processus seems to be reliable in respect to list my own digital licenses which I bound to different Microsoft comptes. Cependant, some périphériques du second list ("We ne peut pas reactivate Windows depuis lese périphériques" ) migrated après some days vers le first list ("périphériques which can be activated"). But this ne matter as the périphérique entries stay the same.
And of course il n'y a pas de guarantee that périphériques which are shown dans le first list can be reactivated avec the périphérique avec which you are actuellement checking the license. E.g. when I check avec my machine virtuelle J'ai aussi get some digital licenses dans le first list which belong to a different périphérique class (e.g. standalone PC). Je suis sure that a transfer from a license like this to a VM would not work in reality.
