But if he is not going to single-position train then buying $1M prospects doesn't make sense to me. However, what you could do is buy not brand new prospects but 19-20 yr olds that have already been single-position trained for a season or two, and then work them into the 2 position training.
The other option is to just hold on to it and see how you are doing. If you feel like you might be in jeapordy of relegating you could get some FAs to help keep you in DIII if not actually compete. But I would also suggest an upgrade to superior trainer.
Since your arena is already built there is really nothing else to spend your money on. You could change the name of your arena every week I guess :p