Brandin10,
Since I just recently purchased an electric pressure washer and have used it a few times on my ride, I will guess at an answer. I would say, as long as you keep the nozzle relatively at a safe distance, lsp issues shouldn't be an issue. However, I'm sure you'll agree, holding the nozzle close to achieve a higher level of dirt removal is almost irresistable.
I would guess holding the nozzle too close would push a wax around. As far as sealants and coatings, I have no clue; I can't even guess.
I'm sure you'll enjoy your new pressure washer though. It's satisfying to see dirt blasted out from between bady panels, seems, wheel wells, wheels, etc where a hose just wasn't as effective.
It's too much fun. I'll trade some lsp issues for the benefits of a pressure washer anyday. See my signature. I believe a pressure washer does a more thorough job than a hose IME.