If Spawn or Ghost Rider can't kill Alucard on a conceptual level they can't kill him. Unless you're saying Alucard doesn't have Schrodinger in this fight which is rediculous considering that Spawn is in the fight.
Penance stare does not attack on a conceptual level. Are you aware that since Alucard has Schrodinger he can't die unelss he himself wants to? As it is he is omnipresent with Schrodinger as he can go wherever he wants, including someone's mind. This is demonstrated in how Schrodinger himself was killed with a blessed silver bullet through the brain and came back later like nothing happened, and how Schrodinger himself appeared in the mind of Zorin Blitz.
SilverGalford do any of these characters have the ability to attack on a conceptual level? If not then they can't kill Alucard.
Schrodinger literally makes it so he can only die if he accepts his death, and he is aware he has Schrodinger's power, so it wont' happen. It is basically schrodinger's cat put into an ability which makes Alucard extremely difficult to kill. He can't die unless he accepts his death or his concept is erased, which is why I said conceptual attacks would be required.
@CerusSerenade: actually time and space are concepts. spawn can erase will or even consciousnesses from anyone and only responds to MoM which is a multiversal being. by reality i didnt meant just the matter, but also concepts like time,will,thought etc. he truly is a god.