Pie chart plot formatting

I am not sure, but I am afraid that your four questions can only be answered by writing code yourself so that you can fully handle the labeling. I post two figures. First, code is given to make a grid that may help you to put labels in their exact positions; therefore just 'uncomment/comment' the ", grids" in the code for the figure.

grids = {
   Table[{Thick, Line[{{-5, i}, {5, i}}]}, {i, -2, 2, 1}],
   Table[{Thin, Line[{{-5, i}, {5, i}}]}, {i, -2, 2, 0.1}],
   Table[{Thick, Line[{{i, -5}, {i, 5}}]}, {i, -5, 5, 1}],
   Table[{Thin, Line[{{i, -5}, {i, 5}}]}, {i, -5, 5, 0.1}],
   Table[Text[
     Style[ToString[i], 16, Background -> White], {3.5, i}, {0, 
      0}], {i, -2, 2, 1}],
   Table[Text[
     Style[ToString[i], 16, Background -> White], {i, 2.1}, {0, 
      0}], {i, -5, 5, 1}]
};

In the first figure I restrict the code by using the call outs of MMA. The pie chart title is now close to the plot. I took the liberty to make three of the long labels even longer by showing the rounded percentage of the whole (0.001/10.003 times 100).

dat = {0.001, 0.001, 0.001, 1, 2, 3, 4};
labels = Table[" ", {Length@dat}];
labeledDat = Labeled[dat[[#]], labels[[#]], "RadialCallout"] & /@ Range[Length[dat]];
fig1 = Framed[PieChart[
   labeledDat, SectorOrigin -> {Automatic, 1}, PlotLabel -> None, 
   ColorFunction -> "Rainbow",
   ImagePadding -> {{160, 100}, {0, 0}},
   Epilog ->
    {
     Text[Style["Donut Plot", Black, Bold, 24], {0.0, 2.25}, {0, 0}],
     
     Text[
      Style["bbbbbbbbbbbbbb (0.1%)nccccccccccccccccccccc (0.1%)n
aaaaaaaaaaaaaaaaaaaaaaa (0.1%)", 13, 
       FontFamily -> "CourierNew"], {-4.6, -0.}, {-1, 0}],
     
     Text[
      Style["aasdadasfsafasfsafasfa", 13, 
       FontFamily -> "CourierNew"], {-2.35, 0.72}, {1, 0}],
     Text[
      Style["afsafasfasfasfasfsafsab", 13, 
       FontFamily -> "CourierNew"], {-0.9, 2.12}, {1, 0}],
     Text[
      Style["casfasfafsafsafsafsa", 13, 
       FontFamily -> "CourierNew"], {2.35, 0.67}, {-1, 0}],
     Text[
      Style["gwegwgwhhtrwhtrjrjwtud", 13, 
       FontFamily -> "CourierNew"], {-0.92, -2.1}, {1, 0}]
     (*, grids*)
     },
   ImageSize -> 800], RoundingRadius -> 15]

In the second figure I also use arrows. Using the code given you can adjust whatever you want. Only as a suggestion, I changed the very small slices (0.001) in something bigger (0.005). This results in a thicker line so that one may recognize that some very small slices are present.

datAlt = {0.005, 0.005, 0.005, 1, 2, 3, 4};
fig2 = Framed[PieChart[
   datAlt, SectorOrigin -> {Automatic, 1}, 
   ColorFunction -> "Rainbow",
   ImagePadding -> {{200, 200}, {20, 20}},
   Epilog ->
    {
     Text[Style["Donut Plot", Black, Bold, 24], {0, 2.2}, {0, 0}],
     (*============================*)
     Text[Style[
       "bbbbbbbbbbbbbbncccccccccccccccccccccn
aaaaaaaaaaaaaaaaaaaaaaa", 13, 
       FontFamily -> "CourierNew"], {-4.4, -0.}, {-1, 0}],
     Arrowheads[.02], Arrow[{{-2.85, 0.21}, {-2.1, 0.07}}],
     Arrow[{{-2.6, 0.0}, {-2.0, 0.0}}],
     Arrow[{{-2.56, -0.22}, {-2.1, -0.05}}],
     (*============================*)
     Text[Style["aasdadasfsafasfsafasfa", 13, 
       FontFamily -> "CourierNew"], {-2.4, 0.8}, {1, 0}],
     Arrowheads[.03], Arrow[{{-2.35, 0.8}, {-1.9, 0.6}}],
     (*============================*)
     Text[Style["afsafasfasfasfasfsafsab", 13, 
       FontFamily -> "CourierNew"], {-1.7, 1.8}, {1, 0}],
     Arrow[{{-1.65, 1.8}, {-1.2, 1.6}}],
     (*============================*)
     Text[Style["casfasfafsafsafsafsa", 13, 
       FontFamily -> "CourierNew"], {2.3, 0.7}, {-1, 0}],
     Arrow[{{2.25, 0.65}, {1.95, 0.5}}],
     (*============================*)
     Text[Style["gwegwgwhhtrwhtrjrjwtud", 13, 
       FontFamily -> "CourierNew"], {-1.7, -2.1}, {0, 0}],
     Arrow[{{-1.7, -2.}, {-1.3, -1.5}}]
     (*============================*)
     (*, grids*)
     },
   ImageSize -> 800], RoundingRadius -> 15]