Seothenoob

The easiest 99 to get is most definitely cooking. It can be obtained in about a week, requires very minimal money compared to the other purchasable 99s, and requires next to no clicking. 210k+ exp an hour at 94 while essentially afking? Prayer can't beat that. Even with Prayer brawlers, I want to gouge out my eyes when I'm done with using them up. With construction you can hardly afk. Cooking even trumps fletching. Fletching requires three inventories to finish 28 bows, which means minimal exp gain. The only thing that makes fletching a better choice compared to cooking is that cooking goods can be a bit tedious to obtain at times, and fletching supplies are(or were, I haven't fletched in such a long time) usually extremely easy to obtain.

If you are safespotting, definitely use void, since the pray and defense bonus given through Arma is useless in a safespot. About the second question, I have no clue.

Firemaking definitely. It has almost absolutely no purpose. Burning shades, lighting candles and torches? Jagex could take out firemaking and let us do these things without the useless moneywaster of a skill.

This is a terrible idea. Along with the already said "omg i'm wearing dh and i have 3 hp and i can't kill this monster or a spirit will attack me", Jagex has already said they are trying to get rid of randoms that don't work. This would probally be one of those randoms that wouldn't do its job. It would be fun for a day, then it would become a nuisance.

Oh and we can't forget how there was never a bank in lumbridge until relatively recently. I remember having to walk all the way to Draynor or Varrock to bank...