Hello
As long as you have the system resources (CPU, Memory) to host these systems then you can. The only restriction that I can think about is that these systems should have different SID and system number. The other thing I can think about is the transport directory. There shouldn't be a conflict in them as well. Each solution should be assigned with different transport directories. BI systems need more system resources compared to ECC. If I were you I would propose to have ECC D & T on one system BI D& T on another server and so on.
I wouldn't suggest setting up all the Production systems on one server like the D and T systems.
Regards
RB