Q: Pre-Retcon Motive for Michael to Target Laurie

One thing you can do is look at sites that have downloadable film subtitles (e.g. opensubtitles.org) or transcripts and Ctrl + F them. I just tried and there's one mention of Laurie by name in the fourth movie and three in the sixth, none of which says anything about a car crash. The only time the word "crash" is spoken in these films is in reference to the one Michael escaped from in The Return. I didn't look for every possible turn of phrase, though.

When we first meet Laurie, her father asks her to drop the keys off at the old Myers house. We see a sign for Strode Real Estate in front of the house, so obviously he's trying to sell it, but no one will buy it due to what happened there. As she approaches the front porch, we see her from inside the house and realize that Michael is there and saw her. From there he began to follow her and probably became obsessed with her.

Q1 is the only real question that necessitates a real answer. And Sandman81 provided it. The rest is a non sequitur in as far as the movies you listed as (other than Part III) all installments after Part II are illegitimate and non-canon since MM and Loomis met their ends in it.

If you look at the first movie only, he doesn't specifically target Laurie. He actually goes after Annie and then goes after Laurie just because she was there.

Myers is interested in Laurie because she appears to be a babysitter like his sister. He's looking to punish irresponsible, negligent babysitters (again, like his sister). That's why he becomes more interested in Annie, as she appears to be more mischievous. He ends up killing Annie because she ditched Lindsey with Laurie instead of looking after her.

When Linda and Bob come over they start making out on the couch and get it on upstairs in the bedroom, taking advantage of Annie's negligence and reminding Myers of his sister and her boyfriend, so he decides to kill them, too (notice he approaches Linda in a disguise/costume like he did with his sister).

When Laurie comes over, she has left the children unattended, and so Myers decides to punish her, too. One of the reasons she survives is because at heart she actually is a good, responsible sitter.

(This bit might just be a coincidence, but I find it funny that after Laurie stabs Myers in the closet, she sends the kids away to get help, and then Myers *immediately* springs back to life to choke her, lol!)