You can probably stock shad in your pond but you will have winter kills every 3rd year on average if I had to guess. What size were the bass when you stocked them last year and what size are they now? Have they exhausted their FHM supply yet? With the addition of tilapia this year, you may want to wait another year before stocking threadfins. Golden shiners can go in this year if you like. Having multiple forage options for bass cannot hurt IMO and is probably a good thing. Get the GSH established before the bass get too large.