Auke1993

If ??? shows up as the original trainer, then I believe that means the original trainer has been banned.

The wiki information you mentioned is likely outdated.
As of a few months ago (I believe), shiny and shadow varieties were made slightly more rare than the other varieties.
The exact rarity is not known, and will likely never become known. However, Shiny and Shadow Pokémon being more rare than the others has been confirmed.

Nightshade Crypt is in Nightshade.
Go into the building that looks like a church, and go into the basement. That's where it is.

Mega Evolutions don't have extra stats. They do the same damage with the same moves.
The main differents are its looks and maybe the Pokémon's type (in some cases).

There are set areas where you can find Zarude. It is not in all areas.
Assuming you are in a correct area, there is a low chance you will find it. It has Legendary rarity, meaning it normally takes a long time to appear. Exact odds are unknown.
Even with the chance known, it remains a chance. You can have good luck and find 3 within 15 minutes, or you can have bad luck and find none in an entire day. It remains a chance, and you need luck to find it.

You currently cannot get an Event Ticket, as there is no even going on.
Event tickets are only given out during some events, and only when you need to get into the Event Center to access the Event.
 

What do you mean by 'Champion avatar'? I do not recall that being a thing. Do you mean the Gym Leaders?
There are eight of them spread across the map. Maybe you missed one of them, or forgot you haven't beaten them yet.
In case you're still missing one or more, this is a tutorial video I've made showing all locations: 
 

Mud-Slap is a Ground-type move. Ground-type moves are normal effective against the Ghost-type.
Mud-Slap is a weak move, so it does not have a lot of power. As there is no multiplier based on Buneary's type, or the Ghost's type, it stays at 33.
If the Ghost-type has another type that affects damage from Ground-type moves like Mud-Slap, a multiplier will apply.
Against a Gastly (Ghost/Poison), Mud-Slap will be super effective, so it will deal x2 damage.
Against a Phantump (Ghost/Grass), Mud-Slap will be not very effective, meaning it will deal x0.5 damage.
Against Drifloon (Ghost/Flying), Mud-Slap will not affect it, so it will deal 0 damage.

You can find all possible Sidequest rewards, including their chances, here: https://wiki.pokemon-vortex.com/wiki/Sidequest

I made a video a while ago showing where all Galar Gyms can be found. You can use that as a guide.
 

You should be able to answer (almost) all your questions about Sidequests here: https://wiki.pokemon-vortex.com/wiki/Sidequest

The announcement lists where you can find it. You can find this announcement here on the Forums, and in the Vortex Discord.
The game's dashboard also links to the Forum announcement that holds the info you need.

As for its rarity, the exact spawn rate is never public knowledge. It is a Legendary rarity Pokémon, so it appears at that rarity. If there is another Legendary in that area, that means both will likely have a 50% chance to appear when a Legendary is encountered.

To my knowledge, barely ever is a spawn like this an increased chance. Nothing was mentioned of an increased chance here.

This question has been asked many times in the past.
This is a guide that hopefully will be able to help you: 
 

The following formula is used to work out the amount of points a player has in the current season.

(√t * √u * √a * ln(b)) / 1000
t = Total Experience u = Unique Pokémon a = Average Experience b = Battle Count

Season Battle Tower: 
The amount of opponents defeated, and the experience received from winning the battle, will contribute towards the player's seasonal points.
Note: Defeating wild Pokémon, gyms, other users, etc. will not count towards the player's seasonal battle count. Only opponents defeated through the battle tower will be considered.


Perhaps a difference in points happened because you won one fight by using one Pokémon, while winning another by using more of them. There's also the chance that the points are rounded off, and that after a certain fights something is rounded up instead of down.

Master Balls catch every wild Pokémon without fail, except for Ultra Beasts.
Ultra Beasts can only be caught with Beast Balls (which catch Ultra Beasts at 100% chance), and Vortex Balls (which catch any Pokémon at 100% chance).
If the Master Balls failed, you'll have been fighting an Ultra Beast.

There are two main ways that I say are the best.
The first is immunity training with level 6 Pokémon. This gives you money the quickest, but requires a lot of Level 6 immunity Pokémon, and can get really tedious.
The other way is Sidequests. It takes longer to get big money, but once you clear a region you get over a million PokéDollars.

I have an answer. This answer assumes you're referring to a Pokémon of Level 100. Otherwise this is harder to calculate.
Fight Gym Leader Erika, and win using 4 of your Level 100 Pokémon (including the one you want this specific EXP on) against her team. You can do this by using a different Pokémon everytime she uses a different one. This should give 176 EXP per Pokémon.
This leaves 95 EXP still to obtain.
This can be achieved by fighting wild Pokémon, beating them with just the Pokémon you want to train. Level 6, and then level 13 should do the trick. So should 7 and 12, 8 and 11, 9 and 10. Any of these combinations should give you 95 EXP.
In total you should have obtained 271 EXP exactly on your Pokémon.

They were a feature in the past, based on the Wonder Trade feature that's been in the main Pokémon games since Pokémon X and Y.
It matches two people together who both are using Wonder Trade, and you trade with each other. You select the Pokémon you're trading ahead of time. So you may get something good, or you may get something bad.
This feature was not used much, and it was almost always used to trade very common Pokémon. It was decided to take down the feature and rework it into something more people would want to use. Until we get to that point, Wonder Trade has been disabled.

As with most rare ones, you likely have a low chance of obtaining it when catching a Blacephalon.

That counts as one battle.
I made a tutorial video a while ago covering all details about the Happiness stat in Pokémon Vortex.
 

You must be in Alola in the Sidequests.
Once you're there, using the Leaf Stone will do the trick.

This is not possible.
When Pokémon Vortex changed from V2 to V3, so much changed that all accounts had to effectively be reset. Everyone had to start over from scratch.
Since V3, all the way to V5 now, players were able to continue where they left off in the previous version. It is expected to stay that way into the future.

Currently this is not possible.
The only way this used to be possible was via the Clan section of the Forums. This Forum section was mainly used for these avatars, which was not its intent.
I can see the Clan section coming back at some point, but after some reworking, perhaps.
If we'll get a Clan Avatar update in the game itself, I don't know.

This likely exists to avoid spammers or bots.
There have been bots in the past that have many many nonsense topics in a short time, occasionally even inappropriate.
This limit likely exists to stop that from happening to a certain extent, among other reasons.

The new accounts puts up a few Pokémon up for trade, the old account offers Pokémon (up to 20 at a time) per Pokémon, the new accounts accepts.
It works the same way as regular trading, except this time you control everthing yourself.