I am well aware of all of this.ruby_onix said:The first four Dragon Quest games were directed (under Horii's main design) and programmed by Koichi Nakamura. His company, Chun Soft, gets credit for all the games up to DQV and I&IIr (SNES).
Manabu Yamana was a (Chun Soft?) programmer on the original DQ, but then he was grabbed for programming the English versions of the first four NES games. He also directed the English versions of DQIII&IV (I&II were NOA's Scott Pelland) He was given the big director's chair (still under Horii, also with Nakamura staying on as a "supervisor") for DQV, and his own company, Heartbeat, got credit starting with DQVI, until he and his company quit Enix before they were able to insert the English translation of IVr which was written and finished by Enix America. Yamana and some/most of his people reformed as Genius Sonority to make Pokemon side games for Nintendo.
Arte Piazza is an art design company that, near as I can tell, is made up of about two to five people. They contributed art design (under Akira Toriyama) on various DQ games. They were credited as working on DQVII and DQIVr, but they weren't capable of inserting a translated script into DQIVr. They apparently made DQVr on the PS2 with the help of Matrix software, the guys who are making the DS Final Fantasy remakes. If Arte Piazza is making these DS Dragon Quest remakes "by themselves", I think that's a secret code meant to mean that TOSE is making them, under Arte Piazza's direction.
As for your last part, it isn't TOSE that's helping with the DS remakes, it's Matrix. They're not credited directly, but many if their staff are.