Yes, the order of completion of your Master Programme Elective (MPE) and Master Free Elective (MFE) does not matter. You can take your MPEs and MFEs during any block, as long as you ultimately complete three electives, where two are MPEs.
If you are planning to go on exchange, we recommend that you take your MFE in Block 5 so you have enough time to drop it after having been accepted to the exchange.