Ditto - A warframe that can mimic other warframe abilities ... maybe with shorter duration/range/strength than the original warframe
eg look at volt team mate, press 1 and you now have the shock ability and you can use is throughout the rest of the mission. The shock damage will be 100 instead of 200 (volt's maximum)
look at rhino, press 2 and now you have iron skin but half the value that rhino player has.
basically, the initial idea was to have some sort of modular warframes from different warframe parts which grants you the different abilities but this one is more of a hijack team mate abilities
as for the powers when there are 4 ditto in a squad, i'll leave that to the community and devs to figure out