Sounds great! When do you think there's time for an update to 1.12.2?
Please consider sugarcane (early game) and cactus (middle-late game) for selling. Both are very server friendly and sugarcane is great for mcmmo if you have plans for that.
I know some will disagree, but having spawn-eggs without silk-picking seems like very interesting gameplay. Imagine people will be forced to find spawners and either hide them or defend them. Personally, I would probably settle for a cave-spider for my string need, given I can sell farm products. Well, maybe a skeleton as well.😉
My preferences would be 1.12.2 (1.13.2), 30K, yes, yes, no, cactus sugarcanes and some beginners treat like dead bushes with a ridiculous sale price. I'm not very keen on allowing silk-picking spawners due to effects on economy, lag and gameplay. I like spawn-eggs though if they are rather expensive. Please promote base building and small-medium factions rather than the usual few large factions with focus on PVP.