In terms of who marries Louis XIV, it would probably go to Margaret Theresa, her younger sibling who would have been 7 at the time of her death. Thus Louis will have to wait until 1665 before even attempting an heir. If her fertility goes as OTL Louis XIV will have to remarry, maybe to an Austrian Princess (and f Margaret Theresa is out of the picture then I can see someone like Marguerite Louise d'Orleans becoming the Holy Roman Empress.
Louis XIV of France (b.1638: d.1715) m. Margaret Theresa (b.1651: d.1674) (a), Maria Anna of Austria (b.1663: d.1710) (b) *1
1a) Miscarriage (c.1665)
2a) Miscarriage (c.1666)
3a) Louis de France, Dauphin of France (b.1668: d.1668)
4a) Miscarriage (c.1669)
5a) Marie Françoise de France (b.1670)
6a) Miscarriage (c.1671)
7a) Louis de France, Dauphin of France (b.1673: d.167
8b) Louis-Joseph de France, Dauphin of France (b.1678)
9b) Miscarriage (c.1680)
10b) Louise-Anne de France (b.1682: d.1690)
11b) Elisabeth de France (b.168
12b) François de France, Duc d'Anjou (b.1685)
13b) Miscarriage (c.1688)
14b) Miscarriage (c.1691)
*1
Leopold I, Holy Roman Emperor (b.1640: d.1705) m. Marguerite Louise d'Orléans (b.1645: d.1721) (a)
1a) Leopold, Archduke of Austria (b.1661: d.1662)
2a) Maria Anna of Austria, Queen of France (b.1663: d.1710) m. Louis XIV of France (b.1638: d.1715) (a)
1a) Louis-Joseph de France, Dauphin of France (b.1678)
2a) Miscarriage (c.1680)
3a) Louise-Anne de France (b.1682: d.1690)
4a) Elisabeth de France (b.168
5a) François de France, Duc d'Anjou (b.1685)
6a) Miscarriage (c.1688)
7a) Miscarriage (c.1691)
3a) Charles VI, Holy Roman Emperor (b.1666) m. Violante Beatrice of Bavaria (b.1673: d.1731) (a)
1a) Margaret Anna of Austria (b.1694)
2a) Miscarriage (c.1696)
3a) Leopold, Archduke of Austria (b.1701)
4a) Joseph, Archduke of Austria (b.1667: d.1667)
5a) Stillborn Boy (c.1669)
6a) Barbara of Austria (b.1672: d.1704) m. Victor Amadeus II of Sardinia (b.1666: 1732) (a)
1a) Miscarriage (c.1695)
2a) Miscarriage (c.1699)