After looking at these three plays numerous times, my perception is that, although the throws weren't perfect, a lot of the blame should be placed on the first baseman. Let me clarify before you bring out the pitchforks and torches. I played first base for many years, in an era most of you think of as prehistoric. We were taught a completely different method of preparing for throws from our infielders that is used today. And I'm still convinced it is a far more versatile method.
Today's first basemen are taught to plant an anchor foot on the infield side of the bag, squarely in the middle, and take a step towards the person about to make the throw. That works great when the throw is good. However, if the throw is off-line, the opportunity to adjust is compromised. You can see in the video that Sano has trouble adjusting on all three throws. The new style of play is not compatible with rapid adjustment. On the first play, because Sano has already made his stretch before seeing where the throw is going, he winds up catching the ball too far away from the baseline to tag the runner. On the second play, having again already done his stretch before the throw is made, he has to cross over his body to try to backhand the throw in the dirt and fails to do it. On the last play, he does the same awkward move but does manage to catch this throw.
Back in prehistoric times, we were taught to straddle first base with the heels of our feet in contact with the outer edges of the infield side of the bag. When the fielder catches the ball, we held our arms up and yelled to the fielder (what you yelled was a personal option - I usually just yelled their name) to give them a reference point. After the throw had been made, we would then adjust our feet with a simple slide step to the side of first base to which the throw was heading. For example, on the first throw in the video, I would have shuffled my feet so that my right heel was now in contact with the home plate side of the bag but still on the infield edge. I would have then stretched parallel to the baseline to see if I could catch the throw without losing touch with the bag. If not, I would step off to make the catch and still be close enough to the baseline to possibly tag the runner. On the next two video examples, I would have shuffled my feet the other way, placing my left heel on the outfield side of the base and stretching towards Polanco. On the throw Sano did not catch, this would have put my whole body behind my glove (and in Sano's case, that's a lot of body). That provides a way to block the ball in case I fail to make the clean pickup. The same is true for the last throw.
I would like to see any coaching staff perform the following simple experiment comparing the way I was taught and the "modern" method. Have a first baseman assume the position currently being used of one foot planted on the bag and the other in a minimal stretch towards second base (any base will suffice). Next, assume the throw is up the home plate side. Have the player make the furthest stretch he can towards home plate and mark the spot to which the end of his glove reaches. Repeat this experiment for a wide throw to the outfield side of first base. Next, do the same two experiments using the mystical methods of our ancestors. I am willing to bet that the ground covered is far greater using ancient folk lore. Try it. I double dog dare you.