Visa Run, Tourist Visa to Spouse Visa

Hello everyone,

with my Working Holiday visa running out in 8 days and I'm about to get married with a Japanese citizen soon, the way of organizing flights and so on gets a bit complicated. Necessary papers for marriage ( certificate of legal capacity to marry) will take a little bit longer than that week. So technically I need like 2-3 weeks in Japan before going to Germany for Christmas.

1) Visa Run or Change to Tourist Visa
As the time isn't enough I want to change to Tourist Visa for that time, so I'm considering going to Korea (seems cheapest option). I saw in some old posts that you can also change to Tourist Visa at immigration by paying 4000 Yen, however I have read different information so that you can get it on the same day or even waiting 1-2 months... Or simply denying it.
In case of a Visa Run, is it ok the actually honestly mentioning wedding plans to the immigration officer in case questions come up reentering Japan? Also, is like going for 2-3 days to suspicious and should I rather go a week?
Also on another note, I applied for the JLPT on 1st December and I'm not sure whether that also could be a justifiable reason to just go like 2 days to Korea?

Any recommendation or (recent) experiences?

2) Visa Application and Holiday in Germany
If everything goes well, I will be married at the beginning of December and can apply for the spouse visa which can take like 2-3 months as I read. Therefore, the application would be done while having a tourist visa and then I should get a stamp in my passport mentioning the application is in process. Once that's done, I'd like to go to Germany for a few weeks with my fiancee.
Would that be any issue for the visa application in terms of timing? Also, I would enter Japan in January again as a tourist...

3) Closing Bank account?
Recently I actually heard for the first time, that as a foreigner you are not allowed to have a Japanese bank account anymore once you it goes beyond the date of your visa ( https://www.shinseibank.com/info/pdf/news190307_fatf_e.pdf )
Actually I would prefer to just keep the bank account (in my case Shinsei) for a few months until the spouse visa is confirmed and the new residence card received.
However, as in my case a new visa application will be started, would be enough of a reason to keep the account?
With still money on it, they cannot just closed the account, right?

Sorry, lots of questions. I checked all similar cases I could find so far, but my situation seems a bit of its own case, so thanks in advance for any help or advice!

2) Not possible. Re-entry permits are not normally granted to people on Temporary Visitor status, so if you leave Japan you must relinquish your status, and that will cancel your application.

I cant answer all your questions, but as someone who has a spouse visa, do not count on your application for spouse visa or certificate of eligibility taking 2-3 months, mine took 5 months and they didn't need anything from me, it was straight forward, they were just behind. It depends on which office you have to apply at etc but just bear in mind it may not be possible to complete on a tourist visa

many questions which I think you should discuss with the correct parties to get your answer.
You can call immigration with your questions and they will give you the answers.

For the bank, true they cannot close your account but they can freeze (lock) your account.
Better to talk with the bank and see the possibilities.

You make it yourself complicated and it seems almost you just do things without really consulting with the parties.

For applying the spouse visa it takes as long as it takes, which can be within 3 months or over 3 months.
Nowadays it seems the process is longer since many people try to apply.

Thanks for your answers so far!

1) Regarding Visa Run immigration doesn't seem to be very helpful, I called them in English and my fiancee called in Japanese both Shinagawa and the airport. Generally reentering could be ok, but with the increased amount of fake marriages in recent years they cannot guarantee anything as it will be a decision of the officer I will encounter. So it seems like a gamble.

2) Cancelling application for going on a temporary trip? Have you heard of such a story?

3) I'm yet to contact the bank. I expect I have to cancel the account even though it seems quite unnecessary. But as you mentioned, they might be a way.