Welcome to E4! Since every new question has questions about how to post pictures, I’m just gonna quote myself here. 
Hope this helps.
To answer some of your questions. 1. Here is everything you need to know when you go through the path of grading through the E4 forum. @funmonkey54 works for Ludkins Collectibles, a well-known and respectable grading middleman located in both the US and UK. Although I’ve only used their service twice thus far, I can certainly recommend them.
-
I’m not really into the grading aspect, but if they have a chance for a PSA-9/10 it might still be worth grading them. But perhaps someone collecting PSA-graded WotC era cards might be better suited to answer this.
-
Do you have a list, album of pictures, or video showcasing them? And I assume you’re talking about all English SM Secret Rares here, not also Japanese and other languages?
-
There are quite a few error collectors in the hobby, and I sometimes buy them myself if I really like them and the price is right. For miscuts @regigigagod is your man. For errors in general @scratchdesk and @fritz can also help you out.
-
If you’re spending 2k per month, you’re already one of the ‘big fish’ here, haha.
Although I have the second largest Pikachu collection in the world and have two cards worth more than 3k, on average across an entire year I don’t spend 2k each month (I hope… 
).
Greetz,
Quuador