Head count is being cut to make this future tie up more attractive to both sides.
For Juniper engineering, it's a net good move, as Ericsson just killed their BNG division. There's a lot less overlap than with Cisco, so only a few Ericsson router and switch people likely to get the chop. Ericsson are an engineering and services led company, and will value your engineering skills.
If you're in Juniper and in sales, be afraid: Ericsson are starving, and inviting you along on this big hunt is their way of getting fed. Despite the handful of 5G radio wins, they are losing the 5G end to end story because Cisco are not desperate enough to do their dirty work... guess who are desperate enough? Juniper. Oh... and just don't look at the Marconi aquisition ;-)
If you're at Juniper and in services, good luck, Ericsson are surprisingly clueless about IP networking, and will be relying on you very heavily for big parts of their 5G story.
You can guess that the Nokia news was close, but not quite right. I expect Juniper have been shopping around Nokia and Ericsson.