Hidden Encrypted Messages

Hidden Encrypted Messages
The following notes/messages/letters are encrypted. Click for hints on decrypting them.
1. Ella's Letter to Leonie (Difficulty: Easy)
2. Xander's Letter to Maya (Difficulty: Moderate)
3. Leonie's Letter to Ella (Difficulty: Moderate/Hard)
Ella's Letter to Leonie
Hint 1 — Ella's Letter to Leonie
Hint 2 — Ella's Letter to Leonie
Hint 3 — Ella's Letter to Leonie
Hint 4 — Ella's Letter to Leonie
Xander's Letter to Maya
Hint 1 — Xander's Letter to Maya
Hint 2 — Xander's Letter to Maya
Hint 3 — Xander's Letter to Maya
Hint 4 — Xander's Letter to Maya
Solution — Xander's Letter to Maya
Leonie's Letter to Ella
Hint 1 — Leonie's Letter to Ella
Hint 2 — Leonie's Letter to Ella
Hint 3 — Leonie's Letter to Ella
Hint 4 — Leonie's Letter to Ella
Hint 5 — Leonie's Letter to Ella
Solution — Leonie's Letter to Ella

The following notes/messages/letters are encrypted. Click for hints on decrypting them.