First question answer is no. They are just purchasing the devices division. The price is about 5.4 b, plus they further license the right to use Nokia technology, aka patents for the price of another 2b.
The answer to your second question will be Here maps, patents which they can licence to other smartphone makers like HTC. and NSN, that is they become Ericsson main competitor overnight. Of course they will suddenly also possess lots of cash.
If you believe in the future success of Lumia line of phones, then yes Msft is the place you should goto. Hope that helps, to other new investors with similar questions as well.