As someone who tried collecting the Kidrobot Simpsons, Futurama, and Family Guy figures, I say DO NOT make a Kidrobot Muppets line for the following reasons.
1) Too Expensive - The Simpsons Series 1 retailed for $7.99. I happily paid that because I was caught up in "The Chase" (discussed below). Then Series 2, and everything after as been $10.99 or more. That price is ridiculous. Heck, the $7.99 price was ridiculous. These are 3 inch vinyl figures with 3 points of articulation, a useless sticker, and (sometimes) a useless accessory. I understand that Kidrobot is a small(ish) company who already charges inflated prices by selling to a niche urban vinyl crowd, but selling licensed properties, which inherently carry a mark-up, paired with their already high-price business model is not worth it.
2) Blind Box Assortment - This is a horrible way to buy toys as a consumer or collector. All this does is incite you to buy more and more based on their fake rarity (mentioned by prior poster, discussed further below) and get caught up in "The Chase." I'll provide an example. Series 2 of the Simpsons had Zombie chase figures of the 5 main Simpsons. Very cool concept and figures, but I probably dropped $150 (or more) buying blind boxes trying to find one. At one time I got 3 Carl's in a row. What am I going to do with 3 of the same figure at $11 a pop. (I did end up with a Zombie Lisa though.) Yes, there is a "Chase" when there a variants on viewable carded figures, but at least you can know what you're getting before you buy. For those of you that follow card games, pretty much every Collectible Card Game besides the established Magic, Pokemon, and YuGiOh has gone under because people don't like to shell out more and more money chasing rare cards. Heck even Magic has been pushing their online game, and Xbox and PS3 versions as a way to counter the backlash from "blind box" cash-grabbing. In the meantime "Living Card Games" like A Game of Thrones, Dominion, Lord of the Rings, and Munchkin are gaining traction in the market using a model where everyone gets the same cards when you buy a box or pack.
3) Fake Rarity - While the rarity is listed on the side of Kidrobot boxes as 1/25, 2/25, or 1/50, there are two problems with the rarity of these figures. In all of their lines, at least one of the chase figures is listed as ?/?? as it's rarity. Who knows how rare it is? It could be 1/100, or it could be more rare...or less, but it makes you chase it. The even bigger problem is the fact that the people selling the supposed blind boxes are stealing all the rare figures. Kidrobot toys in the US are sold at Comic Shops, Urban Outfitters, and some bookstores like Barnes & Noble and Borders, and the boxes are sealed with a hot glue gun by Kidrobot. It only takes a quick internet search to find instances where employees at Comic Shops and even the teenagers working at Urban Outfitters are opening all the figures and simply resealing them with a hot glue gun. This is how a poor sap like me comes along and pulls 3 Carls in a row. I would only assume that an online retailer is doing the same thing, only with more professional equipment, not some teenagers at Urban Outfitters. Also, you can find numerous posts online where people will provide the layout of what order the figures came in in their case of boxes. It's not as shady, but it does provide people with the ability to figure out where in a case the rare figures usually get placed so they can keep those fore themselves, and fille the rest of the case with commons, seal it up and sell it to you. At any rate, if you're trying to buy random boxes to get a rare Statler and Waldorf, you're going to come up with a lot of Kermits and Miss Piggies.
I hate to be Mr. Negative on the subject, but Urban Vinyl collecting is not the road you want to go down. As mentioned before, Kidrobot's business model is to sell to a niche audience who expects to pay an inflated price and that audience already has had a few years of learning the tricks to buying Urban Vinyl and leaving regular toy collectors like you and me wondering why we spent over $100 for multiple copies of characters that we probably didn't really want one copy of.