Whoa....
Why are you looking at a step-down transformer? Also, that is technically a 208 V transformer, though it shouldn't matter.
There are 2 different 200ish Volt systems used. 208V and 220V. The difference is important.
-208V systems are 3 wire systems known as 208Y(not including neutral). The line-to-line voltage is 208V. Each phase is 120 degrees out of phase. The line-to-neutral voltage is 120V. This is common in industrial settings.
-220V systems are 2 wire systems(not including neutral). The line-to-line voltage is 240V. Each phase is 180 degrees out of phase. The line-to-neutral voltage is 120V.
It is important to note that you have 120V in either system. If this is a house, you probably have a 220V. This is how all houses are wired in the US. You receive 220 into your home breaker box. Each switch is either line A or line B. It alternates as you go down. The breakers that use two switches are 240V.
No transformer is necessary. The transformers you see are typically created for foreign power where the 220V is coming across a single wire.
Most large UPS are designed for either 220 or 208. It doesn't really matter, the electronics inside can be switched for either. If you are getting enough VA(volt-amps) to run all of your stuff for 12 hours you will probably benefit from using a 220V rated UPS. When a UPS is rated for 400 VA that means that it can run 400 VA for 15 minutes(however with added batteries you can increase this time). UPS are designed for constant load. You need to figure this out before doing anything else. Do not confuse VA with watts. Watts are true power, VA is apparent power. They are slightly different and way to confusing to explain in this post.
The long and short of it is that you can always use 240/208 power to run your 120V equipment. You don't even need to have a transformer. Either system is actually designed to provide 120V power. A 208/240 rated UPS will probably be easier to procure.
As far as lighting, that gets a bit more confusing because most lighting actually runs at higher voltage. The higher your input voltage, the smaller the transformer. This is only true for fluorescent lighting. LED lighting doesn't matter.