Remember that the positon of "Second Officer" is defined differently in different airlines.
In Britannia and Monarch for example a "Second Officer" is just a First Officer usually with low total hours and new to type who becomes a "Second Officer" until his / her ATPL defrosts.
They are fully type rated and their tasks are that of a First Officer in the right seat, i.e. pretty much half the time as PF and the other half PNF. The only real difference is that they are paid less than First Officers.
The same title is given by some carriers (like Cathay Pacific) to inexperienced pilots who are "cruise pilots", to whom I think you are referring, but this is not strictly speaking the definition of a "Second Officer".