Counterspell and Spellbender together: which one is triggered first?
Actually counterspell triggers before spellbender in any case.
There is an example here on youtube.
I think it's because in the beginning you cast a spell and then you target a minion. This is not an official explanation though.
They will trigger in the order with which they were played. If you played Counterspell first, it will trigger first and counter the spell without triggering Spellbender.
If you played Spellbender first, the spell would target a new minion but then be countered by Counterspell. So you'll end up with a 1/3 minion in your Blessing of Kings case.