I'd stick with the Spanish ECU and worry about the DPF later. All of the manuals indicate that there's no physical difference between the Thai and Spanish ECUs, so either the manuals don't cover those variations (which is odd) or the only difference between them is the programming.
And that raises another idea for another discussion - rather than going to a lot of trouble with DPF delete pipes and sensor replacement and stuff, why not just star-picket the guts out of the DPF and whack in a Thai ECU? It won't care about the sensors so it'll never limp-mode from them.