Those are a little small for embedded Lua, but I think the ColdFire is well within the realm of possibility. But, you're right, native code is still your best bet for those two. I'm an embedded systems guy as well, and I've used eLua previously. I assume you've read this thread about eLua on a ColdFire?
FWIW, I have embedded Lua into a ColdFire. The product ran four Lua instances under separate MicroC-OS tasks. It worked quite well, but we did have to be careful on memory usage – I believe the whole system had 512K RAM available.
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