1. Yes, it is believed Amanda tracked Mez' blood into Filomena's room (where the staged burglary took place).
http://themurderofmeredithkercher.com/Mixed_DNA
This is because Amanda's DNA occurs in the exact spot where Mez' spilt blood was found in a small area.
As for whether any of the others showed Amanda's DNA:
There is also a luminol-highlighted footprint compatible with Raff:
Then we have yet another footprint identified as Amanda's:
Luminol is used by Forensic Teams to highlight blood. It is not reasonable to claim the substance is not blood. And even in the vanishingly remote chance it wasn't Mez' blood but parsnip juice or horseradish sauce, you need to explain why Raff and Amanda dipped their feet in these substances to leave their incriminating evidence at the crime scene.
Finally, how did the court reasonably decide the burglary was staged after the murder?
http://themurderofmeredithkercher.com/Luminol_Traces
You are demanding that criminal courts must have 100% scientific certainty. This has never been the case. The acid test has always been: Beyond a Reasonable Doubt.
In a serious crime such as this, the bar is very high, especially where young adults are involved.
Massei and Nencini were unable to get the kids below this high bar of reasonable doubt.
In other words, each satisfied itself the kids were guilty as charged and the evidence corroborated it.