#1 Will this fit my kenmore elite fridge? i currently have a r-9990 filter in it.
Yes, this model should be able to replace the r-9990 filter.
#2 What are the markings on the neck band like? I need one that has a small square and then a slash mark as pictured on the sampler photo.
The filter is 100% compatible and fits perfectly as LT600p... (LG and Kenmore refrigerators)... The seller may knows more about the filter with a small square.
#3 The description says there are 3 different kinds of filters to pick from depending on your water quality.. I don't see how to order the best one.
there are three options available to help with your unique water treatment problems. You may choose the right one based on your water quality and filtration needs. The NSF 401 certified filters are the best.