Question Is it possible to use the PowerCore alongside other DSP solutions, such as the UAD-1, UAD-2, Duende, Liquidmix or Scope

Yes it is - some of our customers are running these kinds of of setup with great success, though we cannot test nor support any such setup / configuration. However when using both PCI and FireWire based devices, it is important to note, that the available bandwidth is not being exceeded by having too many devices use the same bus.