I swapped my cards around to match your suggestion -- HD5770 = 1, 460 = 2, SSD = 4.
I got the same kernel panic. I tried verbose mode, but the system crashed and rebooted too quickly to capture any info.
Just to be sure, I downloaded the stock BIOS for this GPU, put the card in a Windows box, and flashed the GPU with the stock BIOS (it appeared to match what I already had). Same kernel panics.
Maybe it's just a bad card.
What do you mean by "the stock bios for this GPU?"
I have never done the GPU bios flash. But, there are steps for it on this forum. But, the bios flash are usually for the Sapphire Pulse RX 480 Developer Edition card bios flashed to a different brand RX 580. But, this was prior to 10.13.4 where people had issues with sleep working and cosmetic issues of "About this Mac" GPU identification stuff.
I haven't come across anyone who flashed an RX 460 GPU since there isn't an equivalent Mac Edition RX 460 GPU. There is the mobile Radeon Pro 460 and Radeon Pro 560.... But, again, it's a mobile GPU. So, flashing that bios to a desktop RX 460 might encounter discrepancies not present in RX 580 models.... But, I am not sure.
But, to go back to "stock bios" thing... do you mean you flashed your XFX RX 460 bios to another RX 460 card's bios? If, so, which one? I know from anecdotal experience and from reading other people's experience that the Gigabyte RX 460 version seems to be the one that works OOB with the least, if not, zero issues. And, this is the one I have. The only issue was 10.13.2 Broke Sleep on RX Polaris cards, including RX 460 and RX 580's except for the Sapphire Pulse RX 580. That is why people flashed their RX 580 bios to match the Sapphire Pulse edition to regain sleep function. The sleep bug and cosmetic thing, though, has been rectified with the recent 10.13.4 update.
Also, based on other people's post on here, the XFX version of RX 460 seems to be the one that is encountering the most issues. And, I think, this is also true for XFX RX 580 cards. Correct me if I'm wrong. So, your card is not bad or broken. Just not as compatible, I think. As for which brands? Not XFX. I think after perusing the forums that that is the brand that has the most issues with Mac Pro compatibility.... But, again, correct me if I'm wrong....