re: the template: the class is clearly designed to go with the Shadow-walker template as it specifically states that if you do not have it (implying it feels that entire prereq), you have two other options to enter it. Try to find the Adaptation section to convince your DM.
Dimension Door is the prereq, but any teleportation triggers Shadow Pounce, no?
re: Crinti Shadow Marauder: it gets Shadow Pounce at level 5. You can enter it at level 6. Telflammar gets Shadow Pounce at level 3, IF I RECALL CORRECTLY, and you can enter it at level 8 (with the 10 ranks prereqs). Now, if I'm not wrong, you gain the Shadow Pounce ability at the same time.
re: skills: Remember, as long as its a class skill for one of your classes, the ranks limit stays at character level + 3 forever. If you're human, take Able Learner (RoD, and Factotum).
There's a Feat Rogue variant (trade SA for Fighter bonus feats), and a "Thug" Fighter variant (SA for Fighter bonus feats). Take Able Learner until level 8 (where you enter Telflammar Shadowlord) where you retrain it for a prereq feat because you can apply retraining effects before taking on the next level, thus allowing you to retain the benefit(s) of Able Learner.
Maybe Unseen Seen (PrC, CM) and Hunter's Eye (spell) may help?
There's also some weapon that has the [Teleportation] subtype...
http://brilliantgameologists.com/boards/index.php?topic=3959.0 Warlock's Flee the Scene invocation.
Have you heard of Knight of Shadows or Metus Somnambulus? Knight of Shadows broke Metus Somnambulus's Shadow Pounce record. It involved Ruby Knight Vindicator's Divine Impetus.