Personally I think that maximizing our MPA fleet should be a no-brainer the CAF. Domestic domain awareness (and control) is always a must-have for enforcing our own sovereignty and ASW assets will be in huge demand in a conflict with either Russia or China.
If I were CDS for the day I'd ideally see the P-8 buy increased to 21 to match the size of the CP-140 fleet and I'd convert our 16 x CC-295's to the
MPA/ASW version. For the SAR role I'd replace the Kingfishers with 16 more CC-130J's (which could be re-roled for additional transport capability in case of a conflict).
It wouldn't be adding any new aircraft types to our fleet beyond what we already have so supply chains wouldn't be complicated. Personnel requirements for the increased fleet sizes would be an issue but certainly less of an issue than substantially increasing our RCN fleet size for example.