Just to be very clear about this: according to the Bonvoy membership T&Cs you must stay *and* pay for the rooms to qualify.

The simplest way to guarantee the you get the nights for one room (the one you're in) and the points for all three rooms without aggrevation is to make a single reservation on your Bonvoy account for the three rooms and pay for a single bill yourself at the end of the stay.

Making three separate reservations at the same hotel should also qualify according to the T&Cs but you're at the mercy of Marriott's IT to recognise the different rooms as they post to your account do indeed qualify in the same way. There's plenty of anecdotal evidence on FT that the IT has a tough time dealing with these overlapping reservations even though you should be able to get it sorted out with Customer Service eventually if you've got the folios in your name after checking out of each room.

Now, we get to the tricky bit. You want folios in your colleagues names and you want them to pay. This is a massive YMMV moment because according to the T&Cs you must stay *and* pay for the rooms and (a) the hotel may recognise that you're not paying and flag the reservation as not qualifying for points on your account and/or (b) the folio will not be in your name despite the reservation being made on your Bonvoy account and sorting out the mess with Customer Service after the three separate rooms have posted will be more challenging because CS may see that you've not paid because the folio isn't in your name.

This isn't what you want to hear and you will get plenty of anecdotes of people who have successfully got all the points in your kind of scenario. Just bear in mind that what you want is against the T&Cs and while you can give it a go and may strike it lucky you have nothing to complain to CS about if you don't.