MXP has capacity for 70 aircraft movements/hour (
http://www.seamilano.eu/sites/sea14...._inglese_1.pdf )
MXP actually moves 15000 aircraft/month (April 2018), 500/day, 50/hour for 10 hours. MXP is open 24 hours. (
Traffic data SEA Group )
LIN moves 9000 aircraft/month (April 2018), 300/day, 30/hour for 10 hours. LIN is open 16 hours/day and has capacity for 18 movements/hour so it's actually running pretty much at capacity.
So MXP probably can handle the extra 18 movements/hour even if noone combines a previously separate LIN and MXP route into one route to MXP for the duration.
Terminal capacity?
http://www.seamilano.eu/sites/sea14.message-asp.com/files/imce/scheda_10.pdf says MXP T1 has capacity of 30M/year (after the expansion works completed in 2015). Currently MXP handles 22M/year and LIN 9M/year (wikipedia). MXP has, of course, two terminals.
Essentially MXP is not running at capacity and LIN has less capacity than one might think.
It looks plausible to me.