Yeah it's JEI. You can fix it by disabling the JEI GUI with ctrl+o while on your inventory.

That's pretty much the same thing as the 3 legendary birds currently.

The normal pokemon bosses, like those in the haunted towers are considerably still bosses, but do not drop boss loots. Only the mega pokemons are considered "real" bosses now. Like others have explained above, the mechanics have changed.

Make sure the RAM got allocated when you enter the single player world or a server by pressing F3. It should be on the top right corner. In most cases, it didn't get allocated. Looking at how you're still lagging even with 4-10GB while I'm doing fine with 2.5, that might be the cause. With the pixel...

That would make the orbs exploitable, wherein you can have a friend let you win the battle each time. Kinda like blissey training or power leveling.

You need to allocate more RAM. If you were to open f3 right now you'll see the RAM maxes out every few seconds that's why you're getting those freezes.

Please no.

Just use a chatting NPC that tells the player to pick up the poke loot beside him or something lol. I don't think an NPC like this is necessary.

You can use a resource pack to change how it looks, or the colors.

I believe some of these features are being worked on.