Nur noch 8 Bit Farbtiefe?

The Elements version of ACR will work in 16 bit depth.  You can switch from 8 to 16 bit at the bottom of the ACR dialog. 

The Editor can also edit a 16 bit file.  BUT, there are some limitations on which features will work in 16 bit.  If a feature does not allow 16 bit files, a warning will show up and you will be given the opportunity to convert to 8 bit.  You can also switch between the two in the Image>Mode menu:

You haven't told us how you want Lr and Elements to work together, so I can't comment further on that subject.

Hi @Ditmar LR6 ,

To begin with, when you ask volunteers in the forum, we always start by the advice to download the 30 days trial version of PSE before buying. And if PSE is not adequate for your needs, it's still time to ask for a refund.

From the little information you have given us, it's difficult to say if you have a chance to be happy with PSE.

You only cite 8-bits and smart objects.

Smart objects are reserved to the full Photoshop. Did you use some older version of Photoshop together with LR6?

You are wrong, Elements supports 16 bits for nearly all global edits, but not for layers or detail tools, where 16 bits is no advantage. If your shots are in jpeg, they are 8 bits anyway, if they are raw, they are always processed in 16 bits in the ACR module of Elements.

The crucial question about your project to move to PSE is the state of your library. For PSE to recognize your LR edits, they have to be written to files (in xmp sidecar files for raws, in the metadata header for jpegs, tiffs, psds...)

The more details you can give us, the more we can guide you in your adaptation phase.