2 of 3s1p + 2 of 2s1p
 

2 pack of 3s1p 4000 mah + 2 pack of 2s1p 4000 mah.
Can these 4 packs include to 5s 8000 mah and have any problems, dangerous?

So long as all the packs are from the same manufacturer, have the same C rating, and are the same age/number of cycles, you should be fine. Bit of a wiring nightmare though....