Regarding coax, the only wire I have ever had trouble with was purchased at Radio Shack. That experience was many years ago. The shield had bunched up under the outer insulation during manufacture.
Splitters... most are quite similar in performance. Gold plating and fancy looking cases are cute but don't improve the performance. Look for the loss specification (nominal is about 3.5 dB per port on a 2-way split) and bandwidth should be nominally 5 to 1000 MHz. Additional bandwidth (satellite splitters) buys you nothing in OTA performance.
Regarding grounding, I encourage you to get the most from the relatively small amount of time, money and effort that is usually needed to do the job. Ideally, your tower ground and the coax ground block would be tied to the existing electrical service ground.
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