Hi Mom,
Chag Sameach! I know this is a little late, but I'm catching up after seder.
Rice Chex is not kosher for Passover by any conservative or orthodox ruling. It's not just a matter of it being kitniyot (which is OK if you're Sephardic, anyway), but it processed and prepackaged, thus it could come into contact with non-kosher for Passover wheat products made in the same facility or on the same line. So, even though it's gluten free, it would nee to also have a label stating that the manufacturing process has been checked and that it is specifically kosher for Passover. If there's no distinct seal but there is a kashrut symbol on the box, such as O-U, star-K, or circle-K (the most common kashrut symbols in the US -- there are over 2500 out there!), look to see if there is a P next to it. This indicates that the product is kosher for Passover.
Cheese and yogurt need to be specifically labeled kosher for Passover (again, because of the processing), however milk does not, as long as it is bought before Passover (I buy several cartons and keep it in the coldest section of the fridge. You can also freeze it.) If you're anywhere near the Valley Village area of the San Fernando Valley, there is an AWESOME kosher supermarket -- Cambridge Farms. It's a Vons-sized market with good prices and EVERYTHING is kosher. Many Costco's in this area also have a lot of kosher for Passover products.
Here's a URL for the Passover guide we use (DH is a conservative Rabbi):
http://www.rabbinicalassembly.org/sites/default/files/pub...
BTW, here's a note on the plastic ware. Over the years, I've accumulated a "second kitchen" for Passover. We use glass plates (can be kashered in between meals simply by washing, so they can be used for either meat or dairy) and regular metal utensils. I inherited odds and ends from my Mom, and also kept old sets when I needed to replace our regular dinnerware. Alternatively, you can buy relatively cheap sets at places like Ross or Target, or even piecemeal at dollar stores, then just put them away year after year. We clean for chametz and "lock up" anything that's unopened in our outside freezer or the garage, which really means that we simply cover it over with a sheet of aluminum foil in the freezer and an old sheet out in the garage (of course, we symbolically sell the chametz, too). When it was time to purchase some new pots and pans, I put the old meat ones away for Passover if they were metal, and bought a really cheap set for dairy. The goes for the cooking utensils, knives, etc. It's OK to leave kitniyot in the house as long as you don't use it (if you're ashkenazi), so rather than schlepping all of the stuff --including the regular dishes and cookware--out to the garage, we simply close up the cabinets and put a piece of tape across them, then build a set of modular wire shelve to use for the Passover dishes and supplies. We bought metal cube shelves at Costco several years ago, and use them year after year. About 10 years ago, we moved into a house with non-kasherable countertops and sinks, so I simply clean these items, then cover the counter with reusable, heavy-duty plastic cut to shape, and put wash buckets and a mat into the sinks. I know it sounds like a lot, but it only takes a couple of weekends to accomplish everything (one to clean out the pantry and the fridges, and one to clean and prep everything else. We start immediately after Purim, as per the Talmud, by making a point of eating through our chametz and buying as little as possible throughout the month. This helps us start the process of reorganizing anything that's gotten junky over the year, so by the time we need to clean it's not an onerous job.
A lot of people really go to extremes for Passover, and much of it's really not necessary. Many Conservative Rabbi's will tell you that a lot of what people do to prepare for the holiday is "narischkeit" - nonsense that is not based in halacha (Jewish law). They keep practices that are outdated for the time, simply because their parents and their parents parents did something a particular way, with the reason (if there really was one!) lost way somewhere in the mists of history. In my personal opinion, I think we often spend too much time thinking about the restrictions and the rituals, than on what their significance is. It is just as important that we make ourselves aware of and clean out our spiritual "chametz" to prepare for the holiday, as it is for us to clean our homes.
Kol tuv,
R.