My set-up to kick off the challenge was to have a married couple on the smallest lot in game to save money, which I then made a micro-home with the lot traits Child's Play, Good Schools and Study Spot. I built only 3X3 toddler room with beds, a bathroom with the cheapest sink toilet and tub/shower, the cheapest fridge a toddler toilet, dollhouse and toybox, cheap bookcase, activity table for kid's drawings, kid's chemistry set and the cheap kid's violin.
Next I had each sim adopt a child, form a club made of the family members, adopt a toddler and adopt another child to have a full house. The kids spent a little bit of time playing with the toddlers while the other adoptions went through, then had the adults focus on the toddler skilling while the kids immediately joined scouts and then started to work on their aspirations, beginning with social. I had the club set to make socializing worht points and bought Rally the Troops as my first priority so none of the 4 kids or 2 adults would need to pee, eat or sleep for the rest of the challenge. Then I bought parenting skill boost to help get second wind faster, to help minimize how much time the toddlers would need to sleep.
The next goals in club were to buy the kid skills and homework boost. I also made fishing worth club skills, and cycled a lot of the other club activities to reflect what the kids were working on, such as playing on equipment or doing homework, playing musical instruments etc to boost points faster. Dad fished when kids were at school if toddlers were sleeping, and mom painted sometimes.
I decided to have the kids cycle through and max all childhood aspirations for the bonus points and also skill gains, and was very sad to see the toddlers didn't get happy childhood boost due to a current bug? I have no idea if they actually skilled faster for maxing all toddler skills or not. I didn't realize until I had already maxed a few non-child skills that those skills [like violin and fishing] would be worth a 0 in my multiplier so that was my first big oops moment.
As soon as kids came home from school it was homework first, then skilling until it was time for school again, swapping activities to an aspiration or badge earning as needed. No child was allowed to age up until they had all 4 aspirations, all 4 child skills, and all 9 badges on top of an A grade. The toddlers aged up pretty quick, and one ended up being a teen on the same day as the 4 adopted kids, while the other toddler wasn't able to age up until a day later. I kept everyone in the club mood Inspired as there are a lot of skills that progress quicker in that mood compared to others, and had the parents join jobs once there were no more toddlers to have enough money to buy more skill-items. The money trees were taking too long to grow.
Once the kids had points I bough skill-boosting traits for them [night owl, morning sim, savant], and connections. All six teens managed to top out 4 part-time jobs, and 2 almost got one more. I might've managed more if I hadn't gotten bit by the bug that brings sims home if you load a saved game while they were already at work.
I cycled through skilling to lv 9 in between school work and jobs, spending one day at the gym with energized as my group trait. I should have taken them to the gym with Bracing Breezes in the lot trait in hindsight to get that skill up faster.
I had so many skill multipliers that some skills more then leveled at once and that hurt my multiplier a bit. Baking, cooking and gourmet cooking in particular I had it happen where I would begin a dish at skill 7 and completing it went from 98% on 7 all the way to maxed out. So, then I bought books, and if your skill was higher then 6 you had to read to level it. Which made buying the skill reward Speed Reader a must.
I didn't want to travel for Selvadorian skill, so I sent them to classes, and then realized it was a great way to do the 5-level skills, having them leave class early if they hit skill level 4 while they were there to avoid maxing out. Vampire Lore was another cheap skill, as you can get to lv 14/15 fairly quickly.
Meditating was a bad call for wellness skill, as the sims can have an 'a-ha!' moment and gain skill in another seemingly random skill. I accidentally maxed at least one skill this way before moving them to yoga once I made sure it wouldn't also accidentally max their athletic skill.
I could have gotten an even higher multiplier if i'd thought about changing my lot traits to reflect the skills I was working on at the time, but micro-managing 6 teens at once and anxiously watching the feed to make sure no one accidentally maxed out a skill again had most of my attention. I also missed out on New Skill Day by one day in-game. I should have started in fall/winter to take advantage of that day, I was too busy thinking I didn't want the holidays to force my teen sims to miss work to realize my kid sims wouldn't need those school days.
I also apparently suck at part-time jobs and maxing jobs quickly, its been my downfall in most challenges and dynasties XD
The teens maxed out Barista, Fast Food, Retail Employee and Lifeguard with two also almost maxing out Baby Sitter.