There has been much written about eggs going "fungusy" by which I think most people mean that they have gone white. Is this really fungus though? When I tried in vain to breed angelfish many years ago, the eggs went fungusy then, but it was clearly a white furry like coating. I have never seen that on front eggs - they go white, but not furry and then they break up. I'm not convinced that this white colour is due to fungus but more due to the fact that the egg is unfertilised and just bad. I'm not convinced that this whiteness can spread to a fertilised egg. If this is the case, then there is no point in using methylene blue on the eggs to prevent "fungus".
I may be wrong, just throwing it out there for your thoughts.

I have yet to breed my fronts... they will take a while. But I breed corys, half the time that you have a white egg that you don't remove it will get fungus and that fungus will damage the eggs around it.
I agree that the whiteness is just a bad or unfertilized egg. But removing it will help prevent fungus from getting a foothold.
I have tried with and without methylene blue on coy eggs and I have a better hatch and survival rate when I do use it compared to when I don't.

I hope that helps some... I know you were hoping for front egg info but the best I have is corys

If the egg is unfertilised then it dies and the fungus already present in the water moves in, as the egg has no immunity to the spores.
Which in turn leaves the fungus to spread to fertilised eggs-again the eggs have no immune system yet to fight it off. Thats why you should remove any dead white eggs to prevent the fetilised eggs being infected.
Fugus infections are majority of the time secondary infection, so if a fish' immune has been comprimised in anyway then the fungus can establish itself.