Hero99 has it right. Let's look at how we get there.
The OP is correct in saying that V(C) = V(B) + Vce, but this isn't a very useful "truth" as Vce is a function of a lot of things that we can't know (even if we know the transistor specs, the actual values cover a span that makes predicting Vce vs. Ic not worth the trouble here.)
So what are the useful truths?
1. V(B) must be equal* to V(A) if the op-amp is working correctly. (What is the output of IC1? Who cares? Provided V(A) is sufficiently far from the power rails, V(out) is going to do what it has to do to make V(B) == V(A). )
(* I'm using the word "equal" to mean "pretty damned close.")
2. So now we know the current through R1. it is V(A) / R1
3. We have reason to believe that the current gain of Q1 is sufficiently high that Ic is pretty close to Ie. We also know that the current into the + terminal of IC2 is very small. So, the voltage at C is going to be Vcc - Ic*R2 = Vcc - Ie*R2 = Vcc - V(A)*R2/R1
4. This is also going to be the voltage at the bottom of R3. So the current through R3 is (Vcc - V(C)) / R3
So we crank the algebra handle and get
I(R3) = (Vcc - V(C))/R3 = (Vcc - (Vcc - V(A)*R2/R1) / R3 = V(A) * R2 / (R1 * R3)
5. Finally, we look at the output fet and know that drain current and source current are equal, so Iout = V(A) * R2 / (R1 * R3)
We never needed to know anything about transimpedances, saturation currents, phase of the moon, or anything peculiar.
We do need to check a few things though.
If V(C) - V(B) is negative, then we've got V(A), R2 and/or R1 values that are out-of-whack and this analysis needs to be adjusted a bit.
In fact, if V(C) - V(B) is "too small" where "too small" is a matter of taste, but 0.2V is probably "too small", then we need to adjust the analysis.
If V(A) is too close to either power rail (depending on the op-amp selected) then this circuit will misbehave.
Similar arguments apply to V(C), R3, and the voltage at the Iout node.
Big take-away here, is to look for the simplest rules that will constrain the values you're looking for. Ohm and Kirchoff are most likely to be the best first choice. The only other "rules" we used here were to assume that Av for both op-amps was really high, and that Q1's beta was high. Looking at Vce was a less useful path, as its value is influenced by many factors that are difficult to know or vary with time, place, phase of moon, manufacturing lot, and so on.