just add the line

    <ValidTerrainType>HillsTerrain</ValidTerrainType>

This should allow you to raise hills into mountains.

For the other, add

<ValidTerrainType>Land</ValidTerrainType>
<ValidTerrainType>Rugged_Land</ValidTerrainType>
<ValidTerrainType>Fertile_Land</ValidTerrainType>
<ValidTerrainType>DesertTerrain</ValidTerrainType>
<ValidTerrainType>SwampTerrain</ValidTerrainType>
<ValidTerrainType>ArcticTerrain</ValidTerrainType>
<ValidTerrainType>Forest</ValidTerrainType>
<ValidTerrainType>Beach</ValidTerrainType>
<ValidTerrainType>Cliff</ValidTerrainType>

But there is already spells that do this... called

Curgens Volcano and Destroy Land (earth 4).

Yes, in the xml you will find

<SpellResourceCost>
    <Resource>Mana</Resource>
    <Amount>5</Amount>
</SpellResourceCost>

Change 5 to whatever number you like.