Dear Wally,

I think this would all depend on the intention of the priest regarding transubstantiation.  For example if the priest is suffering doubts and is struggling in his faith during the Mass, but still intends to offer the sacrifice despite his own personal failings, then I think that transubstantiation would still occur.  Remember that it is God himself who causes the change, the priest's role is to consecrate the bread and wine and offer the sacrifice to God.

On the other hand if the priest is openly defiant of the church's teaching, either open with himself alone or publicly, then he would not intend to consecrate the bread and wine and therefore transubstantiation would not occur.

Of course I should mention that obviously a priest like this needs to be removed immediately and a decision on his return to ministry not made until this problem is resolved.

About your other question: if the celebrant lifts them both at the same time at the offertory then he is not following the rubrics correctly.  However it is not serious enough to invalidate the Mass.  Regardless, he still must raise them separately.  There is no room for personal preference at this point in the Liturgy.

Mr. Slavek