Vizkopa Guildmage

• WWizards of the Coast2017-11-17
  Official Ruling
  In a Two-Headed Giant game, Vizkopa Guildmage’s delayed triggered ability causes the opposing team to lose twice the life you gained.
• WWizards of the Coast2017-11-17
  Official Ruling
  Multiple instances of lifelink on the same creature are redundant.
• WWizards of the Coast2017-11-17
  Official Ruling
  Each time Vizkopa Guildmage’s second ability resolves, a delayed triggered ability is created. Whenever you gain life that turn, each of those abilities will trigger. For example, if you activate the second ability twice, let those abilities resolve, then gain 2 life, each opponent will lose a total of 4 life.

Rulings via Scryfall