'eis' used in the sense of 'because of'
εἶπεν οὖν ὁ Ἰησοῦς Ἄφες αὐτήν, ἵνα εἰς τὴν ἡμέραν
Then said Jesus, Let her alone: against the day
τοῦ ἐνταφιασμοῦ μου τηρήσῃ αὐτό· 8 τοὺς πτωχοὺς γὰρ
of my burying hath she kept this. 8 For the poor
'eis' used synonymously with 'dia' and 'hoti'; 'because of' - 'have need of'
καὶ ἐάν τις ὑμᾶς ἐρωτᾷ Διὰ τί λύετε;
And if any man ask you, Why do ye loose him?
οὕτως ἐρεῖτε ὅτι Ὁ Κύριος αὐτοῦ χρείαν ἔχει.
thus shall ye say unto him, Because the Lord hath need of him.
'eis' - 'because (He was)'
κρατῆσαι ἐφοβήθησαν τοὺς ὄχλους, ἐπεὶ εἰς προφήτην αὐτὸν εἶχον.
they feared the multitude, because they took him for a prophet.
I am not trying to be condescending or rude but, I really do not understand what you are trying to demonstrate by these passages, and I am not sure you do either. Εἰς is NOT used synonymously with διὰ or ὅτι. With the genitive, the preposition διὰ can mean 'by', 'through', or even 'during'. With the accusative it can mean 'because of', 'on account of', or 'for the sake of' but, it is not used synonymously with εἰς. The only preposition I know of where εἰς is sometimes used in the place of is ἐν, and that is because εἰς and ἐν both carry basically the same meaning. ὅτι on the other hand, is a conjunction that means, 'that', 'since', 'for', or 'because'; it is not a preposition and is not interchangeable with εἰς.
In your first example, 'against' is a rather poor rendering of εἰς in John 12:7. Since it expresses purpose in the sentence, it would be better translated as 'for', not 'against'. Please allow me to explain. How εἰς is translated in a phrase depends on the action it takes in a sentence. If it refers to special action it is usually either 'into', 'toward', or 'in'. If it express temporal action it is 'for, or throughout'. If it expresses purpose, it is 'for', 'in order to', or 'to'. If it demonstrates result it is 'so that', or 'with the result that'. If for reference, it shows 'with respect to', or 'with reverence to'. If it describes advantage it is 'for'. If it demonstrates disadvantage, it is 'against'. (Clearly, εἰς does not convey the idea of disadvantage in John 12:7.) If it expresses point action, it is 'at'. BUT, it is NEVER 'because of.' Εἰς never takes an action that points backward in time.