My prediction is that we will see a “Fir” batch after Purism finishes delivering all its Evergreen pre-orders, but it will just be the current design based on the i.MX 8M Quad with the RAM increased from 3GB to 4GB and the eMMC increased from 32GB to 128GB and a few other minor tweaks.
I say this because the 14nm i.MX 8M Plus doesn’t support DisplayPort, which is essential for outputting video to an external monitor, and has a worse GPU and VPU performance than the 28nm i.MX 8M Quad, so the Plus would be a downgrade. NXP still hasn’t released a quad-core SoC for the i.MX 9 series which can match the i.MX 8M Quad and it will probably be years before a new i.MX 9 SoC is adequately supported by mainline Linux. After investing so much dev work into the current design, I really doubt that Purism is going to switch to another chip like the Rockchip RK3566. It wouldn’t want to use the same SoC as the PinePhone 2, because Purism can’t compete with PINE64 on price.