LXP uses the hold sheild rewrite for BeX to add characters. since its wifi safe. Its not really that hard to use.
in the ProjectM folder is the RSBEXP.txt file that has all the codes included. you can find the code there.
BrawlEX Hold Shield Rewrite v3 (LXP) [Legacy Team, PyotrLuzhin, ds22]
* 046847BC 60000000
* 046847C0 48000008
* 4A000000 90000000
* 1619C600 00000080
* 7B017C03 04050607
* 08090A0B 300D0E0F
* 37111213 14311617
* 18191A1B 1C1D1E1F
* 20217D23 7A252627
* 28292A2B 2C2D2E2F
* 30313233 34353637
* 38393A3B 3C3D3E3F
* 40414243 44454647
* 48494A4B 4C4D4E4F
* 50515253 54555657
* 58595A5B 5C5D5E5F
* 60616263 64656667
* 68696A6B 6C6D6E6F
* 70717273 74757677
* 78797A7B 7C7D7E7F
* E0000000 80008000
* C268482C 00000006
* 39800000 3C809019
* 6084C600 2C0C0028
* 4182001C 7C0CE800
* 41820010 398C0001
* 38840001 4BFFFFE8
* 8BA40000 00000000
* C2685BE4 00000007
* 39800000 3C809019
* 6084C600 88640000
* 2C0C0028 4182001C
* 7C032800 41820010
* 398C0001 38840001
* 4BFFFFE4 7D856378
* 90A1003C 00000000
[5th to 9th line] The CSS slots in the code are stored in byte pairs,
ranging from 0x00 (mario) to 0x27 (Sonic). The first row reads 00
01 02 03, which translates to Mario, Link, Donkey Kong, and
Samus. If you wanted to put a BrawlEX clone (let's say 3F) over
Mario, for example, you'd replace the green 00 in the code with
0x3F.
the bottom explains how to use it.