I think some complex model with backflow etc cannot be ruled out. Certainly from what I have read I dont think I could make a call as to whether the pot and the appearance of individualised graves date to the same time. There is some evidence that perhaps is reasonably reliable for a settlement site or two that place beaker pot in the 2800-2700BC range but I dont think the same can be said about the burials. I dont think until the reservoir effect is looked at that we can rule out that the radiocarbon dates on human bone are coming in a century or too older than reality. I think this is of the utmost importance because the sudden move from collective to individualised burial is far stronger evidence of a male intrusion than the pottery is.
My complete guess is that there may have been a phase of contacts between the west Alpine area and Iberia via the Rhone and southern France which marked the establishment of the network but that was then followed by a migration of central European males to Iberia in later generations. The clearest evidence for that such a network existed is the early beaker phase c. 2600BC when beaker linked Iberia to southern France and into the south-west Alpine area. However, I wonder if this was just the developed stage of the network and would speculate that such a link could have existed in a less visible way since 2800-2750BC. The main evidence of this would be that the model which the beaker pot was based on looks to have come from central Europe - something that at least suggests wives could have been being traded between the two areas.
The clincher would be if it was shown that Iberian copper was penetrating into west Alpine Europe in the period 2800-2600BC before the beaker culture per se spread along the south of France and into the west Alpine area because that would be the clearest motive for establishing such a network. As for a male intrusion from central Europe into Iberia I think the key is revisiting the individualised graves and their dating checking for reservoir effects. That is far more clearcut than pots.
Pots are normally a female craft. It has also been suggested that Sion indicates that the early beaker phase also saw the introduction of fancy textiles but again that is a female craft. I would also suspect buttons and awls are female associated.
That really just leaves the archery aspect which appears in the beaker phase at Sion. However its very hard to interpret that because archery was common across Europe and from memory Alpine groups like Remedello had a lot of archery equipment - and of course the Ice Man. Even when the stelae were showing the Remedello daggers, we know from the graves of that culture that they were also big into archery. So, there is no simple way of implying origin from the elevation of bows and arrows to higher status. It is odd that they rose in status because they were the least exclusive sort of weapon and on the surface it seems they would normally have been not even involved the use of copper.
I think the best idea is to forget the pots and possibly female crafts which could have been linked to a two-way network involving mostly female movement. Look at the dating of the individualised graves again.