Thats great that you are getting Holly a companion! I have Oliver who is 2.5 and I just got Bentley who is 4.5 months! They have so much fun together.
The one thing I can say is that I had forgotten what a handful a puppy is---even though he is the easiest, most laid back pup ever! I constantly have to keep my eye on him and take him out for frequent potty breaks. If you are gone that long each day without a guarantee of someone being able to come in the middle of the time for a potty break, thats a long time for a young puppy to hold it. Of course, you could do piddle pads, but I think that make potty training harder and confusing for the puppy! Im sure others will weigh in with good advice, too, but I think I personally might be more inclined to go with the older pup if you're sure its healthy and from a reputable breeder!
Good luck with yoru decision!
Holly, Oliver, Rosalita, and Scarlett