As referenced in this thread:
Yes she can invent it and acts as a Mad Scientist for all purposes of the card.
The cost of inventing a Gadget is as follows:
1) Boot your Mad Scientist,
2) Pay the Gadget’s ghost rock cost,
3) Then perform a skill test using the dude’s Mad Scientist skill rating.
Valeria must treat herself as a Mad Scientist or she can't ever perform step 1), ergo she must be treated as a Mad Scientist for The Wretched's.
That first line of The Wretched is now redundant because rules to invent Gadget Dudes didn't exist at the time the card was printed.
As specified in the thread linked above:
Matthew Rising Sun is not a Shaman.
His text specifies that he does not gain Shaman while casting a Totem.
Therefore he cannot use Weaving or any Totems that refer to the casting Shaman.
Additionally since Kung-Fu isn't a skill, an attached Tlalocs Fury has no effect on his ability to cast Totems.
The difference in this situation is the specific requirements for inventing are met with Valeria as noted above and Matthew Rising Sun has specific restrictions:
Matthew can cast Totems as if he had Shaman skill equal to his Kung Fu rating (he does not gain the Shaman keyword while casting a Totem).