I would like to know if there is a night train option from Frankfurt to Barcelona. I will be traveling this route in late April.
No, there's no overnight train. The only option that includes an overnight train requires three connections. Looking Up Train Schedules and Routes Online gives you the Deutsche Bahn train schedule link and tips for using it.
Trains tickets will also be expensive no matter what, since you'd need at least two high-speed TGVs to make the trip in one day. If using a rail pass, the direct Paris-Barcelona TGV is one that definitely limits the number of places for pass holders and later April is very busy with holiday travelers.
Flying is usually quite affordable; see www.skyscanner.com for more budget airlines.
I would fly unless you have serious moral or psychological reasons why you don't want to. The train journey will be long and expensive whichever way you go.
The website/app Rome2Rio is useful for getting information on transportation between two places.
If you do decide against the flying option, you can do this Frankfurt to Barcelona by train, changing only once in Paris. It basically involves all day on the train, no big deal if you know what you're doing.
I would suggest taking the early Frankfurt to Paris Est ICE train. Get the adv discount ticket for that leg, at 39 Euro 2nd class, arriving just before 10 am.
The 2nd leg Paris to Barcelona on the TGV departs at 14:07, which gives you 3 plus hrs for getting over from Paris Est train station to Gare de Lyon and time for lunch at the station too. You can take the Metro from Gare de l'Est to Gare de Lyon or the bus which stops outside of Est, across the street, close to the Monoprix market. I know the area around Est well.
Arriving in Barcelona is at 20:34. In 2011 I did part of this ride round trip, leaving from Gare de Lyon on the TGV to Perpignan, 5 hrs, then changed to a regional train for another 30 mins or so.
Logistically, doing this entire route can be done easily, ie, one change of trains. The train option is available if you deciding on that.
Thank you, all, for your tips . . . They were very helpful 👍😉