It seems you look on a ferric deficiency. Ferric deficiency is shown in the young leafs first like in your picture. Also Lemon trees need much Ferric. And Ferric is transformed in soil very fast to an unusible product.
Therefore I would recommend you to use a leaf fertiliser (liquid fertiliser) instead of granule. Also you should use chelate instead of salts like ferrous sulphate.

But please make sure, that there is not to much fertiliser in the soil and just to less Ferric. Burned (necrosis) leaf tips and edges is a sign for to much fertiliser and shown in your first picture. But you cant go wrong with Ferric chelate fertiliser.
I hope that was useful.