This is the correct answer.
The metals and their alloys (the bold are the "two new metals" and the bold and italics are their alloys, and the italics are not part of the original ten):
Iron and Steel
Tin and Pewter
Chromuim and Nicrosil
Aluminum and Duralumin
Zinc and Brass
Copper and Bronze
Cadmuim and Cerrobend
Gold and Electrum
Atium and Lerasuim are "god metals" and will produce new metals if combined with each of the other 16 metals (this is confirmed at the end of Shadow of Self and the Bands of Mourning), and are thus not considered two of the 16 metals (this includes their alloys, of which Malatium is one [Gold + Atium])
As far as Marsh is concerned: No, we do not have a confirmation of which powers that Marsh has. We know that Marsh was already a Bronze misting, a Seeker, and was given a second Bronze misting spike, and then he was given (probably) all of the other "eight basic metals" from the original series, a spike that allows the burning of Atium, a Gold Feruchemical spike (for healing), a steel Feruchemical spike (for speed), a pewter Feruchemical spike (for strength), and an Atium Feruchemical spike (for age). I believe that is all we have confirmed from what Marsh has used and it accounts for only 13 different powers. There are 16 possible different Allomancy spikes (although this does not include atium) and 16 Feruchemical spikes, so he could have any of the other spikes, assuming that he has not added any since the catasondra)
Marsh also puts his eye spike back in or at least he has in the time period of the Second Trilogy, so I assume that he also puts back his chest spike.