Most CATV systems are designed to have a signal level of 15-20dBmV at the tap on or pedestal. RG6 loses ~6.55dB/100ft, so doing the math tells you about how much signal strength you should have at the house.
While yes, a slitter is a power divider, in CATV the measurement is signal strength, not power. dBmV, mot mV. 2-way splitters lose from ~3.2dBmV to 4.2dBmV, depending on frequency an manufacturer.
3 devices should rune just fine with just a splitter, while 4 or more may need to be amplified.
Splitters used in CATV are bi-directional. The bandwidth is 5-1000MHz. The return path is 5-42MHz, while the forward path is 50-*1000MHz.
If there are digital channels in a cable system, those residential modulators can't be used - digital cable uses the bandwidth all the way up to 750MHz, 860 in some systems.