Japanese Credit Card Acquisition Questions

I would appreciate your help. Here are the questions:
1- does doing a part time job reduce the chances of getting a Japanese credit card?
2-I applied several times, some companies take only 20 minutes to check while others said it may take about a month, how can this be explained?
3-Some companies never ask about the details, name of the country of origin and others while others do, how can that be explained?
4-Is there any quick way to obtain a Japanese credit card for someone who is married to a Japanese over 4 years?
Thank you for your support.

1. If you compare a part-time job against a full-time, regular employment, yes.

2. Some credit card companies boast their "instant issuance" convenience (meaning instant screening), while others function more like traditional financial institutions.

3. I do not know.

4. My non-Japanese husband got one when he was employed by a Japanese employer (full-time).
If you are the non-Japanese spouse with part-time job, would it be an idea initially to get one family/companion card off your Japanese spouse's credit card account?

Do you really need a credit card, anyway? I have one, but the only thing I couldn't do without it is pay my MVNO cellphone bill. Other than that, it makes life just a tiny bit more convenient but it's not at all a necessity. In particular, many things that can only be done by card in other countries, like online purchases, can be done without in Japan.

Every company will be different. Generally, steady employment and a solid residency class (esp. Permanent residence) will aid greatly.

However, I suggest you try for the Rakuten Card. They don't require PR, and seem pretty open minded towards foreign applicants.