1. Does the magic number relate to strategy's ID I sort in the collection before exporting to Portfolio ea?

There is no connection.

When you export a single expert, the Magic Number is the current time stamp.
When you export a Portfolio Expert, the Magic Number is the 1000 * Base Magic Number of the portfolio + the strategy index.

Comment out or delete the strategy Entry and/or Exit signal function call. For an example see the second strategy (with index 001 because the indexes start from 0).

void SetSignals(Signal &signalList[])
  {
   int i=0;
   ArrayResize(signalList,2*strategiesCount);
   HideTestIndicators(true);

   /*STRATEGY CODE {"properties":{"entryLots":0.1,"stopLoss":0,"takeProfit":36,... */
   signalList[i++] = GetExitSignal_00();
   signalList[i++] = GetEntrySignal_00();

   /*STRATEGY CODE {"properties":{"entryLots":0.1,"stopLoss":0,"takeProfit":74,"useStopLoss":false, ...*/
   // signalList[i++] = GetExitSignal_01();
   // signalList[i++] = GetEntrySignal_01();

   /*STRATEGY CODE {"properties":{"entryLots":0.1,"stopLoss":0,"takeProfit":29,"useStopLoss":false,...*/
   signalList[i++] = GetExitSignal_02();
   signalList[i++] = GetEntrySignal_02();

1. Does the magic number relate to strategy's ID I sort in the collection before exporting to Portfolio ea?

2. If the first question is true, If I remove some strategy and stay keeping the others.
How to code it? For keeping the rest of strategies don't change its magic number from an original.
(For example, I will remove the 2nd magic number.
First,3rd,4th number is the same strategies and keep working, But 2nd will not trade)

Sorry for my bad English,Hope you understand it.
Best regards