If a Defender is given a 18 defense by Rookie IG, can he transmit it to an other adjacent Defender ?

(possible standing position below)

IG / Dr Strange / Taskmaster / Beast

Yes. Defend works just like Defenders, including the so-called "transitive property" of passing the value down along a chain. In effect, both the power and the ability transfer the printed value to the next character.

Yes or have IG a defender and doombots in a chain all having 18 defense. as long as they somehow connectued to a defender.