My question is this:

The Phoenix force Namor fragment allows a character to use defenders, now will a character possessing defenders (GG dr strange 106) be able to pull the defense from the Phoenix force figure (say puck antman chaos war)? Or is this where using and possessing comes into play? If not this could be... AWESOME! 23 defense stranges at range, or if hindering, 4 damage dr stranges with 23 defense at range.

Use vs. possess is not an issue here.

This is also done easily enough with asm Dr. Strange;

GATHER THEM: SECRET DEFENDERS OR MIDNIGHT SONS?: At the beginning of the game, choose one: Dr. Strange and adjacent friendly characters can use the Defenders team ability; or Dr. Strange and adjacent friendly characters can use the Mystics team ability, but only to deal damage to adjacent opposing characters.

Also remember that because only the word "use" is being used that you can chain this from as far back as you can make an adjacent chain, keeping your Ant-man way out of reach