I was hesitating whether to get one for my mum. Definately glad I looked them up and found this post, it helped to confim my doubts.
- "To selected households" but no address on it.
- Dated 07/01/2019 but it was in my letter box 08/01/2019. Must be super urgent and special to get here that quick 
- Nowhere in the letter do they call it a coin. Its just a "commemorative".
- "flawless mirror-like quality" uhh al-foil is mirror-like too
although it still has the rising sun on it so either they got permission to put it on there or they are happy to pay the fine
NIce to see this thread is still helping people. 
A few points to note in the recent coments:
Re: the Rising Sun. As noted on the comments ont he previous page, Macquarie Mint have shown themselves to be less-than-perfect in abiding by foeign law, they'e usually very careful about not technically breaking Australian law. All their coin designs that I have seen (and I haven't seen the 2018 one) don't actually feature the word "ANZAC", nor the rising Sun badge or anything else protected from foreign import or commercialization by Australian law. The Australian flag and the Slouch Hat are not protected icons, so they are free to get their made-in-China coins stamped with those images on them.
Second, regarding the legal tender status of the coins. Following the debacle with Nauru back in 2010, they have used Kiribati as their flag of convenience. I assume they actually asked the Kiribati government for permission to issue these coins this time, which should mean that yes, the coins are legal tender in Kiribati. However, in terms of instrinsic value, the coins only contain about AU$3.50 worth of silver at current silver prices, so actually getting your your money back, now the six-month window on the coins has closed, would be almost impossible. There is still almost no demand for these pieces on the secondary market, so local dealers are reluctant to pay above bullion price for them. I think the fellow currently trying to sell on e on eBay for $50 is being very, very optimistic.
The people on Kiribati use Australian dollars in everyday trade: they have always used Australian banknotes, and the coins they made for themselves way back in 1979 have all been snaffled up by tourists by now, so all the money you actually see is Australian. I seriously doubt anyone over there, not even the local bank (Kiribati only has one bank, which is 75% owned by ANZ), would give you AU$10 in exchange for one of these coins.
Given that Kiribati has no central bank or currency laws of its own, I would assume Australian legal tender laws are in force. So, under Section 16(1)(d) of the Currency Act, assuming these coins are actually "legal tender", the maximum amount of such coins which you are allowed to tender in payment of a debt in Kiribati would be ten coins. So, unless you were planning on travelling to Kiribati, somehow getting into debt with someone for less than $100, and paying your debt with ten or fewer of these coins, then the coins are pretty much useless to you, in terms of being objects of money.
