Alternatively, what about taking a train through the Zuid/WTC station and connecting to tram no. 5 (direction: Centraal Station)? Does this option make more sense? And is it indeed faster and possibly more reliable?

Tram no. 5 does NOT stop in front of Le Meridien. If you get Tram no. 5 from Zuid/WTC, you have to get off on Beethoeven Straat, stop Apololaan. From there, you turn right and walk about 10 minutes [beware, if you turn left you will end up in the nearby Hilton Hotel]. The Hilton is much closer to the Tram 5 stop than the Le Meridien (if you can, I would change hotels). Do you have many bags? If so, you better catch the Connexxion bus.

Rgs,