Hi, again

With the suggestions you gave I managed to obtain the functionality I need,
almost.
Somehow letters with accents like á ã é ó õ and also ç don't get the same
color of the base letters given in the colorfont.lfg below:

return {
     name = "coloralphabet",
     colorschemes = {
         default = {
         [1] = { "A", "a", "á", "ã", "å", "à", "ä" },
         [2] = { "b", "B" },
         [3] = { "c", "ç", "C", "Ç" },
         [4] = { "d", "D" },
         [5] = { "e", "E" },
         [6] = { "f", "F" },
         [7] = { "g", "G" },
         [8] = { "h", "H" },
         [9] = { "i", "í", "ì", "I", "Í", "Ì" },
         [10] = { "j", "J" },
         [11] = { "k", "K" },
         [12] = { "l", "L" },
         [13] = { "m", "M" },
         [14] = { "n", "ñ", "N", "Ñ" },
         [15] = { "o", "ó", "õ", "ö", "O", "Ó", "Õ", "Ö"  },
         [16] = { "p", "P" },
         [17] = { "q", "Q" },
         [18] = { "r", "R" },
         [19] = { "s", "S" },
         [20] = { "t", "T" },
         [21] = { "u", "ù", "ú", "ü", "U", "Ù", "Ú", "Ü" },
         [22] = { "v", "V" },
         [23] = { "w", "W" },
         [24] = { "x", "X" },
         [25] = { "y", "Y" },
         [26] = { "z", "Z" },
         },
     }
}

The MWE follows below:

\setupbodyfont[plex,22pt]

\definecolor[colorscheme:1:1][h=002776]  % a
\definecolor[colorscheme:1:2][h=009c3b]  % b
\definecolor[colorscheme:1:3][h=17737e]  % c
\definecolor[colorscheme:1:4][h=ff5733]  % d
\definecolor[colorscheme:1:5][h=493367]  % e
\definecolor[colorscheme:1:6][h=7c6d11]  % f
\definecolor[colorscheme:1:7][h=117c2a]  % g
\definecolor[colorscheme:1:8][h=6d109d]  % h
\definecolor[colorscheme:1:9][h=08d11a]  % i
\definecolor[colorscheme:1:10][h=a81163] % j
\definecolor[colorscheme:1:11][h=7d2830] % k
\definecolor[colorscheme:1:12][h=2868d1] % l
\definecolor[colorscheme:1:13][h=2c11da] % m
\definecolor[colorscheme:1:14][h=cf47bb] % n
\definecolor[colorscheme:1:15][h=27bde2] % o
\definecolor[colorscheme:1:16][h=dc5777] % p
\definecolor[colorscheme:1:17][h=c28201] % q
\definecolor[colorscheme:1:18][h=ffdf00] % r
\definecolor[colorscheme:1:19][h=30a777] % s
\definecolor[colorscheme:1:20][h=722548] % t
\definecolor[colorscheme:1:21][h=ff00ff] % u
\definecolor[colorscheme:1:22][h=e0115f] % v
\definecolor[colorscheme:1:23][h=004c4c] % w
\definecolor[colorscheme:1:24][h=ae0001] % x
\definecolor[colorscheme:1:25][h=696966] % y
\definecolor[colorscheme:1:26][h=7bb3ff] % z

\definefontfeature
   [MyFeaturesA] [default]
   [goodies={colorfont},colorscheme=default]

\definefont[MyFontA][SerifBold*MyFeaturesA]

\starttext

\setfontcolorscheme[1] {\MyFontA BRASIL brasil órfão ÓRFÃO mão MÃO bênção}

\stoptext

What needs to be changed?

Greetings

Marcus Vinicius