I don't know why every character isn't a jamboree buddy since it limited the buddy system depending on who you and your friends play as, so I create some buddy effects and what their minigame could (me not super creative so just work with me on some of these)

• Toadette ~ After you use an item / Let you use another item
• Toadette’s Garden Frenzy ~ Help Toadette plant and harvest as many flowers as possible in a wild garden, gain points for harvesting flowers, 3 rounds of different gardens (Similar to Crops 'n' Robbers from Mario Party 8)
• Player Advantage ~ Gain 3 points
• Toad ~ At an item space / Always get an item minigame
• Toad’s Balloon Burst ~ Pop as many of Toad’s balloons as possible while avoiding the dry bone balloons (Similar to dream shooting from Mario & Sonic at the Olympic game)
• Player Advantage ~ Gain 5 points
• Pauline ~ After winning a minigame / Always get double coins (must get first place)
• Paline's Superstar Concert ~ Guitar hero of Jump-Up Superstar & Honeylune Ridge: Escape basically
• Player Advantage ~ Easier to hit notes
• Birdo ~ Before hitting the dice / Can wrap to the closet shop
• Birdo's Fashion Show ~ Memorize Birdo’s fabulous outfits and recreate her look by selecting the correct clothing pieces, accessories, and poses. 5 rounds
• Player Advantage ~ The wardrobe carousel spins slightly slower
• Bowser ~ While moving / Call fake bowser on any player you pass
• Bowser's Fire Roulette ~ Avoid the bombs set by Bowser’s giant wheel, which will randomly land on different sections of the area. The player who gets hit the least by bombs over 5 rounds wins (Similar to Bowser's roulette rage from Mario Party 10)
• Player Advantage ~ Can move a little faster
• Goomba ~ Before hitting the dice / Use a reverse mushroom on a player of your choice
• Goomba Gathering Challenge ~ Collect the most Goombas after three rounds of varying challenges involving Goombas! The winner is the player who catches the most by the end. Round 1 - Goomba Bowling, Round 2 - Trap-Ease Artist, Round 3 - Paint Misbehavin’ (with More Goombas)
• Player Advantage ~ Gain 5 extra goomba on the bowling game
• Shy Guy ~ Before hitting the dice / Use a single payday dice
• Shy Guy's Mask Hut ~ Collect as many Shy Guy masks as possible within the time limit while avoiding decoy masks and obstacles. collect the most to win
• Player Advantage ~ Move a little faster
• Koopa Troopa ~ Before hitting the dice / Use a cellular shopper
• Koopa's Shoreline Adventure ~ Race along a beach shoreline, be the first to reach the treasure chest at the end of the shore to win
• Player Advantage ~ Gain a shell shield for 10 seconds
• Monty Mole ~ When opponents use an item / Grant protection from creepy dice, swap mirror, & pummel chest
• Monty Mole's Minecart Madness ~ Ride down a minecart track collecting the most to win, 4 rounds (Similar to handcar havoc but solo)
• Player Advantage ~ Gain 10 coins at the start
• Boo ~ When an opponent is at a boo space / Grant boo steal immunity (Basically the Boo repellant)
• Boo's Blasphemous Maze ~ Navigate through a dark, eerie maze filled with Boos, traps, and hidden paths to find and collect cursed items before the other players, first to collect ten wins
• Player Advantage ~ The camera moves a little far to see more
  
• Spike ~ While moving / Give a loadstone to everyone you pass
• Spike's Spiky Showdown ~ Avoid being hit by spiky balls thrown by Spike while trying to knock out other players by hitting them with spiky balls of your own, 5 rounds of different arenas, points based on who dies first
• Player Advantage ~ Gain a rapid spike ball attack (use for one time)
• Ninji ~ When passing someone / Turn them invisible & skip any board events for the next turn
• Ninji’s Stealthy Streak ~ Complete a series of stealth challenges where players must outwit the other players and avoid being caught by Ninji’s detection system. The goal is to collect hidden scrolls while sneaking through the level without triggering alarms or getting caught
• Player Advantage ~ Gain a Stealth Cloak for 10 seconds
• Credit to Oragnge Toad_18 & Infyte for some of the ideas