yes correct 

Hopefully, further announcement on this opening will see Japan accepting Sinovac like UK, US and some European countries

they don't recognize it.

so just hole up in your house until travel day, take the darn PCR test and submit to mySOS app (their mysejahtera) before arriving in Japan.

the rest is essentially pre-covid liao, just mask up as usual

Yes. Feels like too many days in tokyo.

2 full days at Kawaguchi can be a bit overkill unless u like to just relax and do nothing, looking at scenery. I would swap one day from Kawaguchi to Kyoto but if u don't like temples/shrine then that extra day can put in Tokyo.

i used eva airline and did the same as yours, layover at TPE airport when i flew to and fro tokyo.

1. Don't understand this question. If you got 3 jabs of vaccine then u don't need to do any testing prior to flying.

2. taipei - osaka will do

3. TPE airport terminal is really really huge so a lot of places for you to rest. While you can find places to sleep there, normally the comfortable one or the paid resting armchair one will be used by other people, so prepare to be uncomfortable. If you have a 20 hour layover, may i suggest going out of the airport instead of waiting in the airport for so long?

My first Icoca card was brough from Convinence store. If you got Suica / Pasmo, then forget about Icoca. Unless you are card collector.
If you going Kyoto / Osaka Station / Shin-Osaka Station then JR Haruka will be no.1 choice. If you going Osaka city (Namba) then Nankai will be no.1 choice.

Osaka Metro Pass just get it at Ticket Machine. Simple & Fast. All Ticket Machine got Japanese, Chinese , English language selection.

Kuromon market already dead without Chinese tourist. My beloved cheapest Wagyu meat shop at Kuromon Market already gulung tikar.
Damm fxxx sad.

Visa usually have problem with JR online payment, try using mastercard

OTP are sent by your bank (Not from Japan site), if u didn't receive, it could mean your account was compromised and number changed to hacker's phone
or the coverage in your area are very bad and you have dropped line (happened to me using XOX n now I switch to Maxis)

Real Pro going Kawaguchiko by Highway Express Buses. 
Just 1/4 price from JR Limited Express "Fuji Excursion"
Faster than Train almost by 30 minute
Free Wifi Onboard
Highway view are way better than train specially morning period approx 7-9am.

I guess their recent update are going backwards, previously I have no problem using my mastercard to buy tickets from JR. only Visa, occasionally have problem.

Last december they introduced loading shinkansen ticket into IC Card and can do it via their new updated machine. Unfortunately, this update rejects both my Visa n Mastercard. (Some foreigners encounter same problem). Had to purchase thru their counter and mastercard went thru.

Just curious, have you tried calling your issuing bank to check what the decline reason was?

Planning to book the Fuji excursion also in the next 2 weeks as well

yoo... u need to call your bank to authorise oversea transaction.
then u need to set the limits.

is it the JR east eki-net website? I had trouble registering because the website cannot verify my credit card