People need both common ground and unique perspective. Some things everyone should know (what does that square icon for save really mean). Other things, we need each person to come at things uniquely (a system where all of the components react the same is a broken system, eg computer viruses on shared standard systems). It's easy to find inspiration in old technology which applies to technology today. EG, Tesla motors took an old forgotten engine design by Nick Tesla and implemented it in the modern age.
I will expose the kid to as much as they have the attention span for. Probably teach each kid different things. EG, one kid will learn basic even though it is outdated. Another will learn one will learn logo even though it is outdated. Both will learn HTML.