Yes, all those places can be visited with a Eurail pass. This map might be useful for planning, as it shows the main routes: https://www.seat61.com/reference/interrail-and-eurail-map.pdf

Bear in mind that public transport is free in Luxembourg anyway. So you only need a pass here for the international part of the journey, or if you have a first class pass and want to travel in first class.

I would recommend you stay away from the TGV, Eurostar, and any ICE train which crosses FR-DE border, as these require reservations (other cross-border ICEs are OK). But you could go one way through France on TER trains, and come back through Germany on ICE trains.

The journey along the Rhine valley via Koblenz is very picturesque. Slightly slower than the main route from Basel to Cologne

Great thank you! Will this map be updated for 2024 travel? 

Are all the routes shown on the mobile Eurail app covered by your pass?

That map is just an overview of the main lines in Europe. There are many more that aren't shown there. I doubt there will be any updates as such, unless a new high speed line is built!

If you type a route into the trip planner, it will tell you “Not in Pass Network” for any trains which aren’t covered by the pass. You can also filter the results to show only trains which don’t require reservation.

I would recommend using www.bahn.com to research timetables, though. It’s more up-to-date than the Eurail app.

Here would be a basic itinerary, avoiding any reservation fees. (There are occasions where you might save a bit of time by taking faster, reserved trains. But actually not much on your trip.)

These are all easy journeys on mostly regional trains. Fairly high frequency too.

Bern to Basel
Basel to Strasbourg by TER
Strasbourg - Metz - Luxembourg by TER
Luxembourg to Brussels by IC
Brussels to Ghent, Bruges, Antwerp and back, by IC
Brussels to Cologne by ICE (not Eurostar)
Cologne to Basel by ICE taking the scenic route via Koblenz
Basel to Bern

There are loads of places you could stop off. Certainly Strasbourg. Maybe the Black Forest on the French/ German border. I very much liked Leuven near Brussels. In fact, I try to avoid big cities, so I wouldn’t necessarily spend time in Brussels. 

SBB has a map for all possible rail connections for passengers in Europe: https://www.sbb.ch/en/travelcards-and-tickets/railpasses/area-validity-map.html . Zoom in if you want to see the smaller lines.

Or you could use www.openrailwaymap.org

It’s waaaaaaaay to early to find exact timetables for August 24. But just look for a random date next week, to see what kind of service you can expect. It doesn’t change that much. There could be engineering works in summer, but a replacement busses are always provided.

Eurail/Interrail validity works via train companies. If the train company is part of Eurail, you can take any train of that company you’lld like. So you can use it on almost all trains in Belgium, Luxemburg, Netherlands, Germany, France (not Ouigo though), Switzerland (Except some touristic railways high up in the mountains)...

But you asked some suggestions:

• If you’re coming from Switzerland: you can enter Luxemburg easily by train via Trier (Germany, and Metz/Thionville (France). Trier is historically quite interesting.
• Going over Germany probably gives you the most flexibility and best train service without overly expensive seat reservation. Excellent suggestion of @ralderton to go via the Rhine Gorge, very scenic route. I adhere to the recommendation.

Other suggestions:

• You could also try to search for a hike between two railway stations, The Ardennes and Luxemburg are ideal for that. Some examples: https://www.visitluxembourg.com/tour/cfl-bahnwanderweg-1-troisvierges-clervaux ; https://www.belgiantrain.be/nl/travel-ideas/inspiration/discover-belgium/walks (not available in English alas)
• The most straightforward route from Luxemburg to Brussels goes westward, over Namur (quaint city, though, not by the likes of Ghent or Antwerp, but pleasant to visit). But the northern railway line from Luxemburg to Liège is more picturesque, with lots of charming towns and hiking possibilities. Quick and easy acces to cities like Maastricht (Nl), Aachen (D) and the Belgian Ardennes. And don’t forget Liège and to admire its stunning Guillemins station too of course .

In conclusion: fiddle a bit around with the search settings on www.bahn.com , by adding stopovers over the places we sugges here for a random date somewhere next week. And you’ll get a clear indication of what to expect next year and you’ll have an very nice holiday in the Benelux.

PS: I don’t really like Antwerp, so I always encourage people to go and discover something else when in Belgium . But it’s your call anyway, plenty of things to see and discover there as well.