You should be able to mine with both the CPU and the GPU cores.
Obviously it cant be any memory heavy algo as its an APU.
I imagine cryptonight would do quite well on the 704 shader model.
The Ryzen 5 2400G is basically half of a Ryzen 1700x so you can assume about 300 H/s on cryptonight.
Not sure how the integrated GPU will work with Cryptonight but based on the shader cores expect at least RX 550 numbers so like 300 H/s. Realistically anywhere between 250-400 H/s.
You be lucky to get 600 H/s total. Not bad if you can find a board that will support 6 cards. Though im sure it will cost a lot more than a basic celery CPU.
I dont think its very lucrative but might be good for mining rigs if its not overpriced. You'd need a Ryzen mobo + the CPU And I cant see them selling the top tier CPU for less than $120, probably $149.99 for the Ryzen 5 2400G.