No, the US is NOT considered the "most liberal" segment of SSPX, and in the past had been associated most with SVs and SV-leaning men. Quite a number of the original band of the Resistance were US-based also.
Fr. Calderón is no "theologian", and he's also 69, going on 70 ... so would be disqualified for that reason alone.
Certainly they would not have chosen any "hard-liners", but few of those who remain in the neo-SSPX could really be considered such, and if the were, they'd be in a mud hut in Nigeria, like Father Peter Scott. Father Griego would have been a better choice from the US. He just turned 60, but he's in great physical condition, and was seminary professor, seminary rector, and of course speaks English and Spanish (a great fit for North America). So, why not? Well, he was at seminary the same time I was, during the early +Williamson era, and many of the original Resistance were from that same group. Father Pfeiffer and Father Chazal were both there about the same time, as I and Father Griego, so that makes him immediately suspect in their eyes, or at least more suspect than a Father Goldade.
Nor am I convinced that the consecrations will happen as currently "planned", but that some "last-minute" deal could very well be announced, and likely has already been pre-planned.