Hi Devyrae! I hope you've had a good experience so far at AA conventions. The idea of themed grab bags (like pink items) is a neat idea! I haven't really seen a lot of customizable grab bags, just pre-packaged mystery bags that you never know WHAT you might get.
I only have one concern about your shop (and aaa please don't think I'm going social justice warrior on you, you are new to AA, and I don't want you getting in trouble!). Your buttons look like they are the original copyrighted images taken from the web. While I know it might seem silly to draw the same symbol you can get online from a show, game, meme, etc. it is actually very illegal to sell art and imagery that you did not draw yourself. If you were to re-draw in your own style (no tracing or re-drawing it line for line) then it is a-ok for symbols and characters to be on buttons and other merch. However, you run into the risk of companies discovering your bootleg merchandise and suing you over something small, which is more costly for you than it is for them. I would suggest brushing up on copyright laws when it comes to fan-art and fan-craft.
This is from the Kumoricon AA FAQ about Fanart:
Can I sell fan art?
Yes. As long as your art is composed by your own hand (no tracing or related activities) and does not violate any copyright laws, you are allowed to sell it. You will be asked to remove any art that does not meet these qualifications.
And regarding your homestuck merchandise: Hussie has expressed in the past that only AU/SPINOFF art/merchandise is okay to sell for profit. However, anything that is direct fanart from the comic requires permission from Hussie himself. Generally permission will only be given if you are charging only for cost of materials, giving it away for free, or are creating something that no one else can. You can draw homestuck characters for commission, however (as it is a one-off item and will not be reproduced). Needless to say, you are not legally able to take images from the comic and sell it as a button (as it is his work, not yours).
Buttons like that could be grounds to ban you from many of the conventions I've sold at. This rule is also upheld at Kumoricon and I would not be surprised if this merchandise would prohibit them from giving you a table :C
I think you will run into less legal issues with the pixel...things (I don't remember what those are called! It's the hot-iron things right? ANYWAY,) because you had to take the time to put the pattern together, but I would still refrain from basing the pattern completely off of copyrighted works from the series.