While an Empy would take a bit more time just to get through the NM phases and get all the pops/items you need, you could totally merc all of the lv80/85/90 items and have plenty of money left over to buy Heavy Metal Plates and Riftdross/cinders.
Eh, you'd maybe put a dent into HMPs.
hmp's have been dropping in price on bahamut lately.
down to 80k/each quite regularly. thats 120 mil for the 90>95 upgrade.
Thats cheaper than a relic atm.