Two flyback diodes in parallel for higher current?
1N400x diodes have a tempco of 100 deg k/W for junction temp rise.
There is no max power rating but temp rise ought to be in the 40'C max range for a decent design.  

instantaneous power @1.2A 0.93V @25'C
Max current no-repetitive is 30A.    

Since diodes have a NTC cooefficient current sharing can lead to hogging so to remain stable IF the current was continuous would require a series R about equal to the tolerance on the ESR with thermal matching. ESR is about 0.25V/1A = 0.25 Ohms if heatsunk.

So for the pump, no problem.