Firstly, Town Councils are not the deciding authority on planning matters, they just respond to planning applications that are sent to them.
Councillors only need to declare an interest if it relates to them or their spouse or partner so in the first example, there is no compulsion for the councillor to declare an interest - they might feel that it is a good idea, but the decision is theirs to take.
The second example, if taken to an extreme, would suggest that if you are friends on facebook, then you can't be involved in any council decision making.... Councillors are required to attend council meetings with an open mind and with no pre-determination but you can't stop them being friends...
Again the only time you are obliged to declare an interest is when it is financial and affects the councillor or their spouse / partner. Councillors can chose to declare non-pecuniary interests if they see fit but the onus is on them to decide.