1) Just because Lucca strips Robo of his body and me saying he's the circuit doens't mean hes dead. He talks to Serge, for freaking hell. He still has his mind.
2)Purple Robot >.< Possible Grobyc?
3) The only scientist that could have helped Lucca is either Luccia or Belthasar. Luccia said her and Lucca worked together on stuff, so anything can be possible here.
4) Don't confuse yourself with time lines. Like Sentenal said in a different post, when they come back from beating Lavos, time doesn't change till 1999AD where theres a new future and up to 2400AD, the time crash occurs.
Now, this is the irony. Since there was no Kid in the time line till after the time crash, that means that no orphanage was discovered. Belthasar appears in 2300AD in a good future, and FATE is accomplished. Now, after the time crash, do you think only then Lucca would have reasons to build the Prometheus Circuit or even a mother board model because it would be Belthasars wish. Basically, I remember hearing that Chronopolis exists both in 2400AD and 7600BC. Going to it like steps into the future etc. So if Lucca built the Circuit in in time crashed time line, one day it may truely have gone to the future Chronopolis. Then theres the whole obduction thing. If Lucca had the circuit in her house or anything, it would have been burnt and destroyed. BTW, where was that purple robot there at the time? >.>
5) Listen to Masato and the interview.