If something is in the pipeline I'm not convinced it would involve moving anything particularly major from PIK, they need it to be open to keep leverage on GLA - Plus the S15 flights from PIK have been on sale a while now, if they were going to move them they would surely have announced that when they went on sale?
FR schedules can obviously chop and change, but the last time I looked at the FR GLA S15 schedule it looked like it needed another based aircraft on Wednesdays from June. One aircraft bases don't seem that common and perhaps don't give the best economies, so imo it's pretty likely they'd look to expand if the existing flights are doing well.