A1shah
'And those whom they invoke besides Allah have no power of intercession;- only he who bears witness to the Truth, and they know (him)'. 43:86
'The day We shall gather the righteous to (Allah) Most Gracious, like a band presented before a king for honours, And We shall drive the sinners to Hell, like thirsty cattle driven down to water,-None shall have the power of intercession, but such a one as has received permission (or promise) from (Allah) Most Graciou. 19:85-87
This intercession is specifically for the Day of Judgement, not today!
The intercessions you quoted were for the Apostles at that time, not years down the line after they have returned to Allah SWTA:
'Not an apostle did We send before thee without this inspiration sent by Us to him: that there is no god but I; therefore worship and serve Me. And they say: "(Allah) Most Gracious has begotten offspring." Glory to Him! they are (but) servants raised to honour. They speak not before He speaks, and they act (in all things) by His Command. He knows what is before them, and what is behind them, and they offer no intercession except for those who are acceptable, and they stand in awe and reverence of His (Glory). If any of them should say, "I am a god besides Him", such a one We should reward with Hell: thus do We reward those who do wrong'. 21:25-29
Moving onto 2:255, I did not forget, I just didn't have time as it was getting late.
Here you go:
In the beginning of the of ayat 253-283 are explained the concepts of Unity of Allah, and that of the unity of guidance through the revelation. Lest we should forget, we are reminded of the Law of Requital.
Then are related the stories of Prophet Ibraheem AS that of one who woke up after a sleep of a hundred years, proving,if any proof is needed, that Allah is Powerful to raise the dead and call them to account. The Believers should keep this in mind and know that life of this world is nothing but temporary and, therefore, they should spend their wealth in the cause of Allah.
It's not a question of discarding what I don't believe, it's called exercising the gift of Choice. I do not believe that I need an Intercessor to speak to Allah. I make Salaat in order to speak to Allah and when Allah needs to speak to me I read the Qur'aan.
I'd rather go direct to the Source rather than via a Third Party. This may seem unacceptable to some, but it's the route I'm willing to take as the Qur'aan tells us time and time again that only Allah has the Power and is directly ACCESSIBLE.
'Allah created all things and He is the agent on which all things depend'. 39:62
' There is nothing like Him and He is the hearer and seer of all'. 42:11
' Whoever trusts in Allah will find Him sufficient'. 65:3
' The decision rests only with Allah. I put my trust in Him alone and all who trust should only trust in Him'. 12:67
' Oh believers, seek help in patience and prayer. Truly, Allah is with those who are patient'. 2:153