Is the question still relevant?

Yes, with the Tolino you can also buy from other booksellers. There are a good dozen suppliers of e-books that are immediately recognised by the Tolino and displayed directly. You can set this up if you wish when you use the Tolino for the first time. I can't confirm whether Exlibris is one of them, because this provider is unfortunately rather expensive and extremely complicated with the access rights (Exlibris is 100% 'tied' to Adobe to prevent possible pirate copies, which is extremely customer-unfriendly in my opinion). Theoretically, however, it should work. Perhaps there are members of our Digitec fan community who actually buy e-books from Exlibris and can report on current circumstances.

Yup actually costs 22 CHF and reduced

Unfortunately, it is not possible to simply load an app onto the Tolino, but it should be possible via root and app sideloading. I also rooted my Tolino 4 to install Android apps, but it was quite a tinkering until it finally worked.

Unfortunately, the Tolino does not have access to the Kindle library. Depending on the DRM, however, you can convert the Kindle ebooks into an Epub, alternatively you can also root the device and then install the KindleApp, both variants are unfortunately associated with effort.

The 7" reader can be ordered individually and costs 229 francs (Digitec price as of 8 December 2019). Here is the relevant link to it: tolino vision 5 (7", 8GB) The charger is only about 3 cm tall. It can also be ordered separately (Digitec daily price 22 francs, 8.12.19). Here is the link to it: tolino USB charger