I'm with those who think it a rather nice link between them, especially since both families seem to be on good terms.
I am old and cynical enough, however, to wonder if this happy situation will remain that way once the new baby arrives and a whole new dynamic, maybe including jealousy — either direction — is set up. On the other hand I'm also old and soppy enough to believe it entirely possible — maybe even likely — that they will find ways together to surmount any such problems and create a brrat big nurturing and suppprtuve wider family.
So, on balance, I'm with the 'think it's cute' crowd.
When I first saw the headline, though, I thought it might be about naming a child after a loss of a child and re-using the name/s for a subsequent one. While I can (I think) understand the urge to do this, including, perhaps, having a long-cherished plan for using a favourite name and understandably not being willing to lose that as well as the child it was planned for, I can't advise strongly enough against this, from personal experience.
A family I knew well did this, right down to using the planned middle name too. (For example, say, Albert Frederick Brown) This had the result for the second Albert Frederick Brown of growing up acutely aware of a family gravestone, one that he saw often, showing precisely that shared name, only with a death date just ten months before his own birth.
Some people might be able simply to shrug this off, but the person concerned never quite could, feeling themselves always to be merely a replacement for the first, much longed-for, baby. Perhaps it's not unusual for any subsequent sibling after loss of a child to have some of this fear, but using identical names can hardly have helped such a tough adjustment.
It had very serious consequences for this child and his psychological development. As a result he fought hard not just for the usual parental approval but to exceed any imagined expectations his parents might have had for the first Albert, and became an extreme exemplar of the belief that it is not enough to succeed: others must fail.
This intense inherent competitiveness, mixed with the weak self-worth underscored by his reaction to his name, sadly (if paradoxically) resulted in cruel egotist who despised almost everyone else, on some pretext or another, a massive snob who habitually delighted in using his high level of verbal acuity to sneer at anyone and everyone who failed to meet his own excessively high standards of achievement including, as a sort of in-house vehicle for his scorn, his marginally less academically brilliant younger brother. As a result he succeeded in passing on to another child a version of his own damage, in a mirror-image of a child who was made to believe he would always fail to succeed as much as his older brother, a weak egotist who developed, in turn, his own version of snobbery and habitual scorn, taking pleasure and finding excuses for sneering at others and bilittling their achievements, a habit that eventually played a large part in the breakdown of our marriage. (I knew he was damaged when we married; my own youthful egotism lay in imagining I could love him enough to make him whole.)
One apparently small decision; such a long trail of destruction
So while I'm not suggesting that any other family might contain the toxic mix of this already dysfunctional and emotionally fraught family, I’d still, nevertheless. strongly but respectfully suggest that anyone finding themselves in such an intense period of sadness and joy as the birth of a child after the loss of another should try to find a way, somehow, to say goodbye not just to the lost child but to the once-cherished names and instead use choose completely new names with which to celebrate in their new child the arrival of an entirely new identity with a future entirely their own. Anything else may put too high a burden on a child with a 'borrowed' name, risking a damaged ego and low sense of self-worth, even in the most nurturing family.
But I still think sharing middle names in a wider family can be a way of cementing the bonds within it. Or, as others have put it, cute!