Yes you can! You can publish your own hosted elevation and hosted tile layer in ArcGIS Online.
For the Tile Layer you want to use as a basemap
You will want to create a tiling scheme for your data which matches the same projected coordinate system you used in your scene layer and publish the tile layer. You could create a tile package and upload that to ArcGIS Online to create a hosted tile layer and then you can use "Open in Scene Viewer" which will open the data in a local scene using that tile layer and you can then add in your scene layer
For the Elevation Layer in your local scene
You will want to use the same tiling scheme but you will need to use a different tiling scheme file. The reason why you will want another tiling scheme file is to define the tile format as LERC. if you do not do this you will end up with another tile layer instead of an elevation layer. Once you have the tiling scheme file ready you can use the Manage Tile Cache tool and then Export Tile Cache tool to generate the tile package which you will upload to AGOL and create a hosted elevation layer.
You can then author the local scene in Pro which can use all the services you published or you can author the local scene in the scene viewer.
Thanks so much for the guidance and such a quick response. Where I was going wrong was in the creating of the tile cache. I was using the AGOL scheme which is WGS, therefore when I uploaded my packages, they were WGS 84.
So now, my process isn't quite flawless yet. Here is what I have done so far:
Publishing local base map
Publishing local elevation
So why would the scene be flat? Have i done something wrong?
Here is the elevation service URL:
Greetings from Zürich