I would have even looser guidelines, but still suggest some facetime in the office if possible. Mostly the team themselves should be able to mandate their own locations and hours to fit their needs. If they are productive...
Some teams may prefer heavy pair programming and thus may need to be most of time in the same location. Others(most) would use some sort of hybrid where the 5 hours 3 days a week probably works well. And then some will be very much independent tasks where then locations are mostly irrelevant apart from whenever syncing is needed and general communications with other teams and stakeholders.
But teams and even when pairing you do not always need to be permanently physically in the same location if they know each other well and can communicate freely across chat and screen sharing etc. However mostly in person will trump all communications.
Way too many times management will try and dictate based on what they think is right without taking in the desires and the makeup of the team. This usually is shown in the form of all hands meetings on a very regular basis -- more than one startup I've been at have fallen into this trap.
"all-hands" meetings are an artificial attempt to instill a social-heirarchy, by elevating the presenters over the rest of the staff. Being invited to speak at an all hands is attempt to award social currency, by telling the presenter that they are special. All-hands have no value, with one exception:
If they provide an open mic for questions, it's a rare opportunity to put an exec on the spot in front of everyone.
Some teams may prefer heavy pair programming and thus may need to be most of time in the same location. Others(most) would use some sort of hybrid where the 5 hours 3 days a week probably works well. And then some will be very much independent tasks where then locations are mostly irrelevant apart from whenever syncing is needed and general communications with other teams and stakeholders.
But teams and even when pairing you do not always need to be permanently physically in the same location if they know each other well and can communicate freely across chat and screen sharing etc. However mostly in person will trump all communications.