KLM must without doubt be planning to fly to Cork if they are dropping their codeshare with Aer Lingus. It will be a big blow to EI as Amsterdam must be their busiest route from Cork after Heathrow.
While I would love to see KLM on the Cork route, I don't think it is going to happen.
KLM are apparently still committed to the EI codeshares - so while they have not loaded them for the period past mid-March, it doesn't yet mean that they won't continue.
At present, it is impossible to buy a ticket combining both KL and EI flights from any agent, so it is something they will probably need to decide on soon.
And as regards EI not being able to maintain 13-weekly service to AMS without KL pax - that was my initial fear, too. However, a bit of research showed that KLM only started codesharing on the route back in 2001, at which time EI was already running 2 daily B737s on the route.
KLM and Aer Lingus To Expand Codesharing | News | Breaking Travel News
Back then, there were six daily EI flights between DUB and AMS. That had slipped to 5 in recent years, and when FR came on the route, it was down to 4.
KL have increased their DUB-AMS offering to 4 daily with the start of the summer 2017 timetable, meaning that each of EI, FR and KL will have 4 daily flights between DUB and AMS.