Leyline of the Guildpact

• WWizards of the Coast2024-02-02
  Official Ruling
  Each land you control will have the land types Plains, Island, Swamp, Mountain, and Forest. They'll also have the mana ability of each basic land type (for example, Forests have ": Add ."). They'll still have their other subtypes and abilities.
• WWizards of the Coast2024-02-02
  Official Ruling
  Giving a land additional basic land types doesn't change its name or whether it's legendary or basic.
• WWizards of the Coast2024-02-02
  Official Ruling
  A player's "opening hand" is the hand of cards the player has after all players have taken mulligans. If players have any cards in hand that allow actions to be taken with them from a player's opening hand, the starting player takes all such actions first in any order, followed by each other player in turn order. Then the first turn begins.

Rulings via Scryfall