There are a couple of schools of thought.
IPA, mineral spirits and solutions like PrepSol remove residual from the paint surface and within any remaining swirls or scratches before the LSP step. Many of us check the level of correction by using IPA or MS. Durability of the LSP is often determined by the ability to bind to the paint surface. The cleaner the surface, the better the bond. These solvents also clean the paint surface so the LSP binds properly.
IPA has a fair or unfair reputation for drying or hazing the paint. MS has a fair or unfair reputation for leaving residual oils. I have used both without issue. The one thing that tends to be consistent is the need to remove old wax residue before using a sealant.
Pre-wax cleaners tend to clean and remove oxidation to prep the paint for the LSP. They typically add oils or something to the paint to enhance the gloss. Some prewax cleaners are LSP specific and some are more multi-purpose. Some sealants want a specific surface to bind, so some cleaners leave the surface with that characteristic. I have 4-5 prewax cleaners in my collection and maybe one is LSP specific.
To paraphrase Mike Phillips, use products that are additive or add benefits rather than substractive before the LSP. Prewax cleaners tend to be additive and solvents tend to be subtractive. To be safe, follow the manufacturers recommendations.
I used finishing glazes with carnauba waxes in the past, so I equate the prewax cleaners to a finishing glaze in some ways. I often go directly to the LSP after the polishing step with minimal or no "prewax cleaning" with a solvent and even sometimes use a glaze.
I suggest that you try different prewax cleaners and solvents to see what you like. Learning is what keeps this hobby (business) interesting.
