Thank you all for your replies.
Some time has past and I did buy the bike.
I had contact with one of the forum members and that was a big help.
In the end I didn’t bring much tools. Just Allan Keys (8,6,4,2) and a 15 wrench.
My intention was to get the bike and walk/carry it home, I travel by train mostly.
However, due to delay and maintenance on the tracks I ended up driving the bike home most of the way!
The seller noted some troubles with the bike, all of them should have been maintenance jobs. Like adjusting a brake or tightening a bolt.
Since I didn’t have any previous experience with Strida Blackstridaaustria’s tips were a big help.
I did miss the wear/bend on the handlebar lock however. Resulting in a loose left handlebar.
I did manage to fix that, I’ll make a separate post for that later.
Also the brake pads didn’t need adjusting. They needed replacing ^^ The pads were worn down to the metal and didn’t brake anymore. I have serious trouble loosening the caliper adjustment bolts. So I ordered new calipers to be safe. And I liked the bright red ones better ^^
To cut a long story short, when buying a Strida you dont’need to bring an entire toolkit. Basically only the Allan Keys are enough.