Have you thought about doing your ATPL subjects before you start the CPL. This way you dont have to sit the CPL exams. It also saves you money. Dont worry about FI ratings at the moment. Concentrate on passing the ATPL exams and then doing your CPL / ME IR and MCC.
At this point I would look at your options and how the airline market is looking.
A FI rating would now be a good way to hour build. Remember that the IR is only valid for a year so the cost of revalidation will need to be considered.
Hope this helps a bit. There will be plenty of other people out there giving different advice. This is my quick interpretation.