I grew up on a dairy farm in northwestern Wisconsin and farming is in my blood. I would be doing it for real had I not experienced a back injury.
As to your questions, my dad seldom spread lime but he did once in a while. I'm not sure what made him decide to spread lime and when to spread it but I think it had something to do with what the agronomist told him after running soil samples.
On your question of whether or not to spread slurry or manure or both, it kind of depends on what sort of system the farm is set up with. On our dairy farm, we only had a system where we had manure and we had to clean the barn by turning on a chain and running the manure into a manure spreader. We didn't have any set up for slurry on our farm but I knew farmers who did have what was called a manure pit where they stored manure from their cattle. Some farmers also owned a manure spreader that they used to clean out pins that were not connected to the slurry system.
On your question of whether to use liquid or solid fertilizer, it also depends what type of planter the farmer is set up with. We only had a corn planter that used solid fertilizer. However, we occasionally had someone from the local co-op come out and spray liquid fertilizer.
I hope my little bit of insight helps you in your quest for a realistic farming experience. I also like to play fs19 with as much realism as possible.