God profession mixed with prepared and maybe stronger starters traits, 50 starter points onto genes/traits, and pick a strong tank/fighter + support combo, preferably with focus as a skill, optionally famous to have town characters as extras after dating them, and you pretty much can go ham right away, or after few ranked arena battles to get extra stats, money and gear. Works fairly well, that is until challenge rank 10+, where king will require a DPS check due to regeneration passive, meaning you'll have to just delay quests until your party is strong enough to beat him.
Your questions, to be honest, become more and more confusing the way they are worded. And harder to answer aside from rather cryptic assumptions, if not outright annoying. But I'll try to answer some that I do understand:
The collection attempt fails because it literally says "no resource left"(or lack of stamina, depending on the situation), so you have to wait for a day till it regenerates, and the game literally tells that, I can't understand how difficult it is. You can also use the farm to gather such resources, if you have the space for it.
The milk resource is gathered from female characters, capacity and regeneration is based on breast size, and species, some have large capacity, but low regeneration, but as long they have larger sizes, it shouldn't be a problem. Especially with the milker upgrade from the barmaid, which allows to focus on something else while the backup party members wait and do chores.
Same goes for semen, its from male characters, and based on the size of their member/species, and with the librarian instead of barmaid special home upgrade for collection.
One hatchery upgrade requires both of those, but generally it is very handy to have, purely because of the special submit quest in the cave, but also of maxed morale that allows them to fight in the arena right away, if their stats/skills are suitable enough.