Random crypto puzzles

[SkyboundSteven]

This is only for fun -- there's no security in those texts, except for really basic encryption.
In the answer, you'll find my letter to everyone. Enjoy!​

1.

A B C C D E D F C G H A I J I J K C I H H C B L F M N H D N O P P C B Q K G B R O J H S D F S O T
(Basic A-to-Z swap encryption)​

2.

241A4D00051D1E54011D190001114D04180E171808584D0D02014A1801540B1D03104D07021908541D151F004D1B0B540A060811191D03131E5424541A150300
08104D0002540A1D1B114D0002540C18015402124D0D02014D04081B1D18085A
(Basic XOR; key is 2 bytes long, a to z)
​

3.

2B1D0006186573216D7472756C0A15216D7472756C65734001185E756C6573216D74720104041D4A6D7472756C657321141B07756C6573216D74721400097321
6D7472756C65154E1F7472756C6573216D1C17191C0C1D466D7472756C65732102001A101E1673216D7472756C6511586D7472756C6573210B1D1C11050B1421
6D7472756C65734E180072756C6573216D74051D0D1173216D7472756C651E4001031307096573216D7472756C0C00216D7472756C65734508071B1202001721
6D7472756C65734702065E756C6573216D747214020173216D7472756C650449027472756C6573216D1D01756C6573216D747216030B075302181E1C02027321
6D7472756C651A55437472756C6573216D2702100F0C124D6D7472756C657321191C131B071673216D7472756C65074E6D7472756C65732120151E020D171610
6D7472756C657321041A72756C6573216D74241C1E1000216D7472756C65736415171A14020216216D7472756C65734302150011406573216D7472756C2C7321
6D7472756C651F440C061C10086573216D7472756C0473216D7472756C651F4E197472756C6573216D15101A191173216D7472756C651E400103130709167321
6D7472756C65124F097472756C6573216D3D72756C6573216D741A141A0073216D7472756C651F440C061C10086573216D7472756C111C216D7472756C657353
08191D03096573216D7472756C111B44007472756C6573216D151C116C6573216D7472750E0073216D7472756C65035308041307090173216D7472756C65154E
1F7472756C6573216D001A10016573216D7472756C0C15216D7472756C65735505110B756C6573216D7472101A0001216D7472756C6573401900131607657321
6D7472756C080A216D7472756C657342021902001800010F00
(Basic XOR; key is 8 bytes long, a to z and ends with "!")​

4.

4C6F70797C6F2A532A6F786E2A7E72737D2A766F7E7E6F7C362A532A7E726B78752A6B76762A79702A83797F2A7A6F797A766F2A70797C2A81726B7E2A83797F
2A6B7C6F452A63797F2A7A6F797A766F2A6B7C6F2A7E726F2A726F7C792A79702A7E726F2A81797C766E2A79702A73787E6F7C786F7E2A6B786E2A83797F2A7A
6F797A766F2A7C796D752B2A5E726B78757D2A70797C2A7D7976807378712A7E72737D2A76737E7E766F2A7A7F8484766F362A6B786E2A726B806F2A6B2A7873
6D6F2A6E6B832B2A3758797C7E728179796E
(Basic byte incr/decr, "Space is the key")​

 

[SkyboundSteven]

The last part of this letter:
[...]p.s. All of this would have been impossible if it wasn't for you. Thank you so much, and keep up the good work everyone!