They are definitely akoyas, take my word for it. That is what Mikimoto does best and what they are primarily known for.
Used (pre-owned) pearls unfortunately don't sell for a lot of money. But many people value the Mikimoto brand name and will pay more for their pearls than they might for an unbranded strand.
However, your necklace needs to be cleaned and restrung, and the clasp either replaced or else cleaned and the pearl replaced. Mikimoto charges a lot -- hundreds-- for these services. Someone buying your strand will factor that cost into what they are willing to pay.
You can look on eBay at SOLD Mikimoto necklaces to get an idea of what a strand similar to yours might sell for. Remember gold is very expensive now so a necklace with a gold clasp will go for more than one with a silver clasp. Then price it accordingly. If it doesn't sell, you can lower the price as needed.
Or you could list it as an auction, with the starting price the minimum you would be satisfied to get for it, and let the market decide the final price.
As to the cufflinks, do a search on eBay for similar mother-of-pearl cufflinks. But if they have no markings, they may be base metal.
