Ok. The Coyote WT (wavetable) is about the worst possible sound for MIDI, so you have a lot of possibilities. PG Music included it for use in 64-bit Windows so people would have something.

Coyote Forte is a different product, only $40 or $50 I think, sold here. It would be a good upgrade. After that, the sky is the limit for hardware synths (from a few hundred to thousands), and similarly for software synths. Have you experimented with SampleTank that comes with the last couple of versions of BIAB? That's a software synth that can give really nice sound and is fully expandable.

I use a Roland Integra7 for my MIDI sounds but those cost over two grand.

About the "ringing/feedback" you hear, that sounds more like an acoustic design problem with the hall. There are gadgets that just monitor and suppress feedback. I would start with EQ first, and then perhaps experiment with changing the placement or direction of the speakers in the hall. But try some detective work to pin it down.

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.