Jake and probably Rachel's last name was Berenson. The others' surnames were never revealed.
The next series is Remnants. It says so in the last book of Animorphs (book 54) in the authors note.The Megamorphs were written DURING the Animorphs.
Tobias dissapeared and Rachel died.
As of my last update, there has been no official announcement of a live-action Animorphs movie being released. It's possible that there may be plans in the works, but nothing has been confirmed as of now.
Animorphs was created in 1996.
Ax gets kidnapped in the book titled "The Alien" which is the eighth book in the Animorphs series written by K.A. Applegate.
The ISBN of The Hidden - Animorphs - is 0439106788.
The Sacrifice - Animorphs - was created in 2001.
The ISBN of The Experiment - Animorphs - is 0590762613.
I can only find the first one for sale and no mention of another one coming out.
The Resistance - Animorphs - was created in 202000-10.
The Resistance - Animorphs - has 141 pages.
The Unexpected - Animorphs - was created in 2000-07.