This is not recommended. The best procedure to achieve this is to have both servers on version 10.2.8.0 and do the backup restore on your new server. When this is done, you can safely upgrade your DataMiner...

In Cube, you can right click the element you want and select 'Properties'. You'll get a pop-up and in there you should find the DMA ID and Element ID. (DMA ID/Element ID)

Yes you can. In the same section of the docs you linked, you can find some examples (https://docs.dataminer.services/user-guide/Advanced_Modules/UserDefinedAPIs/Defining_an_API/UD_APIs_Examples.html)....

Hi, You can go to 'System Center' -> 'User/Groups'. Here you can add/remove the 'Switch Failover' permission from the user/group.

I'm not sure if the slides are available or the raw recording. But there are some Inspire rewind videos as well as some of the Ispire track recording. You can go to Learning -> Video Library and then...