And the way a SWCG makes that chlorine is through the salt content in the water, which is kept higher than a regular manually-added chlorine pool. The salt level is usually about three times higher in a SWCG pool versus a non-SWCG pool that has been going for a while.
Regarding the filter, he is listing a sand filter (24" size). As Tex said, the type of filter is up to you. There are benefits/drawbacks to all three types. Here's a comparison article on the three types.
Pool Filter Comparison - Trouble Free Pool You probably won't mind any type, though DE does require some special care the other two don't. For cartidge filters, the article mentions "tearing down" the filter to get to the cartridges. That is really only removing one bolt and a band, then lifting the cartridges out. Here's the picture of a cartridge.
Pureline Cartridge for Hayward C3025 & C3020 (PA81) - PL0104 - INYOPools.com They last for a long time. Mine are the originals and are 7 seasons old. Mine has 4 of these. It takes 45 minutes once a year for me to clean them because my filter is appropriately large/oversized for my pool. I've never had the other two types but users of each tend to like them.
A Dolphin robot from Marina Pool and Spa (order by phone) costs from $700 - $1,500. Extra cost adds features like Bluetooth capabilities that are not required but some like them. I have the cheapest in-ground model, the S200 or Active 20 and love it. There is a link in my signature about them (very long thread).
One color LED light will be dim for that size pool on some color settings. Two is better to be sure you have enough light for your pleasure. Place them on the long side of the pool closest to the house to keep you from looking into them so much.
A 400K heater costs more up front but will heat the water proportionately quicker if that is of interest. No real difference difference in operational costs, just speed and up-front costs.
I like 2 skimmers for that surface area which are included. They only have 2 returns. I prefer 3 for that size. A little better circulation and flow to the skimmers is afforded by the extra return.