Map-ed programmatic Style-s (based on user-input) are not evaluating. Scoping constructs are suspected

Question

The top function manages several sub-functions which set visual properties over a list of Options.

Inside stylerules the function deconstruct Extract-s parts of a Rule and calls string or symbol for applying appropriate Style-s then reconstructs them.

A whole set of Rule-s is processed by Map-ping deconstruct onto set. Style properties are generated or selected based on user-input for stylerules[set_List, keystyle_, valstyle_, strstyle_] (option rules, keys style, values style, strings style ). For any style argument, user may input Automatic vs True vs any custom Style properties in a List vs None or False (last two default to generic Style-s)

I'm having difficulties with the output. Style-s are not evaluating, which also prevents the deconstructed Rules from reconstructing.

Don't worry, the code below looks a lot worse than it is. I promise that it is very easy to follow. I believe the problem areas to focus on are the inner functions string and symbol which may be scoped wrongly. I tried other scopes which did not help, including dropping initialized variables and constants into the main body. Please help. Thank you.

To reiterate:

1. Why are Style-s not evaluating and how to remedy this.

2. I just noticed that some strange out-of-place Null-s are also appearing in the resulting rules. I don't know why.

(* PrettyOptions 0.7 Prototype 1 Runs - 2 *)
ClearSystemCache[];
ClearAll[set, stylerules];
(* the Echo's are temporary *)
stylerules[set_List, keystyle_, valstyle_, strstyle_] := With[{
    rules = {x_ /; 
        MatchQ[x, Automatic | True | False | None | Null]} -> 
      Nothing,
    keys = 
     DeleteDuplicates[
      Flatten[Join[{Bold, 
          FontFamily -> "Courier New"}, {keystyle}]] //. rules],
    vals = 
     DeleteDuplicates[
      Flatten[Join[{Plain, FontFamily -> "Arial"}, {valstyle}]] //. 
       rules],
    strs = 
     DeleteDuplicates[
      Flatten[Join[{Bold, FontFamily -> "Arial"}, {strstyle}]] //. 
       rules]
    },
   Echo[keys, "keys  [Rule]"];
   Echo[vals, "vals  [Rule]"];
   Echo[strs, "strs  [Rule]"];
   deconstruct[rule_, keysty_, valsty_, strsty_] := With[{
      nbcol = Options[EvaluationNotebook[], FontColor],
      comcol = RGBColor[.75, 1, .75],
      altcol = Lighter[LightBlue],
      a = Extract[rule, {1}],
      b = Extract[rule, {2}],
      fn = Head[rule]
      },
     x = 
      If[StringQ[a], string[a, strs, strsty], symbol[a, keys, keysty]];
     y = 
      If[StringQ[b], string[b, strs, strsty], symbol[b, vals, valsty]];
     Return[fn[x, y]];
     ];
   symbol[sym_, ops_, style_] := 
    If[(ListQ[style] || ColorQ[style]), Style[sym, ops],
     Which[
      MatchQ[style, Automatic], Evaluate[Style[sym, comcol, ops]],
      TrueQ[style], Style[sym, altcol, ops],
      True, Style[sym, ops]
      ]
     ];
   string[str_, ops_, style_] := 
    If[(ListQ[style] || ColorQ[style]), Style[str, ops],
     Which[
       MatchQ[style, Automatic], 
       Evaluate[Style[InputForm[str], Gray, ops]],
       TrueQ[style], Style[str, comcol, ops],
       True, Style[str, ops]
       ];
     ];
   Echo[Map[deconstruct[#, keystyle, valstyle, strstyle] &, set]]
   ];
stylerules[set_] := set;

(*  arbritary data *)
set = Options[TestCases] = {TestCase1 :> 111111111, 
    TestCase2 :> "string222", "TestCase3" -> Symbol333, 
    TestCase4 :> Symbol444, "TestCase5" -> "string555"};

(* a few typical use cases, none worked *)
stylerules[set, Automatic, Automatic, Automatic];
stylerules[set, True, True, True];
stylerules[set, None, None, None];
stylerules[set, Automatic, True, Automatic];

(* this test case works *)
stylerules[
  set, {Blue, FontFamily -> "Times New Roman"}, {Magenta, 
   FontFamily -> "Times New Roman"}, {Orange, Plain, Italic}];