1- Sectorial Only
2- Link Teams are completely different from coordinated, on a link your linked troops move together (always in Zone of Control of the Link Leader) during your Active Turn only the link leader gets to act but gets certain bonuses depending on how many members the link has.
3- Myrmidons can only link with Myrmidon Officers, Patroclus, Fenix, Ajax, Eudoros and Macaon, and only up to four members, on the other hand they get to have as many links as officers they can deploy.
Link Teams are on the Human Sphere Rules, which are here:
http://www.infinitythegame.com/infinity/downloads/rules/%5Ben%5DRulesHS.pdf
4-The enemy can only
ARO to the link once per activation, example: 3 Myrmidons and Fenix, link moves and all enter in Line of Fire of a Sniper, Sniper can Shoot Fenix or any of the other Myrmidons, but only one of them.
5- In Active Turn only the Link Leader can shoot, and he gets the bonuses, in
ARO they all have to declare the same
ARO or the link breaks, yes, in
ARO all members get the bonuses