Well ... there are exactly 28.315 spells available. Query them all will take ~3 seconds and store id, icon path, and name per spell will take ~ 6 MB memory.
3 seconds at onload shouldn't be a problem. But 6 MB?
If you ignore all spells with rank > 1 (should be same as rank 1) you'll need 4 MB only.
You could narrow down the amount of spells. eg. every spell with "(OLD)", or "TEST" in it's name is dispensable. Same should be true with all spells where the icon path is "Interface\\Icons\\Temp". But I guess you'll need at least 3 MB memory to store all relevant spells.
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Why not starting with an empty table? If the player types in a spell name query all spells (will take ~ 3 seconds) and search for the spell name. Of course there will be a delay of app. 3 seconds every time the player adds a new spell. But who cares?