Few question before application

I am planning for naturalization application soon(me, my wife and 11 year old son) as family application. I got ILR November 2018(Tier2 5 years route). I would be grateful for answering few questions:

1. Do we need 2 same referees for all of us or each individually needs 2 referee(therefore 6 total!!) ?
2. Can my doctor colleague be a referee? Although I can see that doctor is not in the list of approved professionals.
3. For my son, a single teacher is unlikely to know him for last 3 years. In that case, can the professional person be head teacher?
4. I have 4 parking ticket(PCN)in last 4 years from council which was paid immediately without any further issue. Reading the whole guidance regarding good character carefully, I can see this is the only matter which can be pointed in my whole application.
Do I need to mention these? If yes then how adverse this might be?

Many thanks

1. Each applicant applies individually and hence requires 2 referees each.
You can use the same 2 for all applications.

2. Yes. But as a colleague.

3.Yes

4. PCNs don’t need to be declared.