As someone who’s Dutch, I was aware of that Trouw-newspaper article mentioning February 24th, 2000, but not of the Pokémon-Paradijs page mentioning a Tuesday (March 1st, 2000).
Regarding Portuguese, we’ve recently tried to figure out the release dates of all Portuguese sets, but unfortunately for the WotC era sets, it was hard to find information. Your March 2000 does correspond to the initial WotC planned release date for Brazil. But if those were the actual release dates, we don’t know for sure.
Two small corrections regarding the Pikachu promos:
There are two different Dutch #4 Pikachu promos. One with stamp that was indeed in the Pikachu World Collection 2000 nonet of September 2000 from Sydney, Australia. But also another non-stamped version (with also slightly different translations - although the meaning is the same), from the VHS of the second movie in October 2002. I’m gonna quote my own collection part of it:
The #27 Pikachu artwork was only released in Japanese, English and Italian. French, German, and Spanish copies of this promo doesn’t exist a.f.a.i.k. The Italian version of this card was also available with stamp from the Pikachu World Collection 2000.