Do you want to see if the scenarios are plausible or how the War is going to evolve by the early start?
For me, the most plausible scenario is the first (the second I believe that will not generate a war because it will be easy for the SPD and the Kaiserreich to convince the French that those 3 are insane and are in no way connected with Germany or the SPD) an even if they are succesful, it will not be guaranteed that it will be enough to generate the chain reaction of secret alliances that started World War I.
The way I see the scenario evolving is like this:
*The 3 French citizens try to murder Kaiser Wilhelm II but fail and murder the Kronprinz instead. The Kaiser, mad with grief, decides to send an humillating ultimatum to France. The Chancellor, Chlodwig, prince of Hohenlohe-Schillingfurst, is again unable to stop the reckless foreign policy of the Emperor. The Faure government, takes the option of using this to unify French public opinion, divided by l'affaire Dreyfus. Considerating the terms of the Ultimatum as insulting to French Honour, the French reject the terms of the Ultimatum and start the mobilization of the armed forces. Meanwhile, the French inform the russians that a German attack will be considered enough reason for activiting their secret alliance (since 1894). Czar Nicholas II declares that Russia will support the French and starts to prepare for a partial mobilization. The Germans, seeing that that the Kaiser´s ultimatum has made war unavoidable, prepare their forces for war and ask the same to their allies in the Triple Alliance. While it is possible that the Austro-Hungarians will join (A Russian Victory over Germany would be bad news for the Habsburgs), the Italians back out because for them, the Triple Alliance is a defensive pact only (and they are too occupied with their abyssinian adventure). After Britain tries to mediate (and fails), Europe marches to war...
And then, you have a war.
It is plausible? I wouldnt say that is not, but it is somewhat difficult to imagine. There are more opportunities to stop the war here than in 1914.After all, there was an interest in the Austro-Hungarian government to use the opportunity of Franz Ferdinand´s assasination to make an impossible ultimatum that Serbia would reject, providing Austria-Hungary with a casus Belli to go to war with little Serbia, and ONLY with Serbia (That the Russians will support Serbia and be ready to go to war defending them wasnt part of the plan). Here, why the german government would not try to stop the Kaiser´s idea of insulting (and going to war) with the French? Why blame France if the murderers are connected with french parties, but not with the French Government? Will Faure decide that Russia and France are finally ready for revanche?
And the War itself?
The situation of 1898 is different to the situation in 1914. Russia´s mobilization will be even slower, because it will be a lot less modernized, giving the Germans time for operations against the French. (However it is not that much, because even the germans are working with Late XIXth Century logistics). Schlieffen is Chief of Staff, but his famous plan was written in 1904, so it isnt ready yet. The Entente Cordiale doesnt exist: 1898 is the year of the Fashoda Incident, and Britain and France nearly went to war during the crisis started by that incident (Another reason why the French will try to not go to war against Germany in 1898.They are preparing to go to war against Perfidious Albion, not the boches).
So that is how I see the scenario. I wish that my opinion was helpful to you and others.