Insider buying and selling, stock repurchasing and shares dilution

Want clarification on some things, if anyone can answer:

1. When insider (CEO, Director, etc.) buys shares – is that considered official company repurchasing or personal investment? When insider buys (in non-corrupt company), it is that their personal money used and not company's money?
   ex. $ASAN Asana CEO was buying A LOT of shares recently – is that official repurchasing or just personal investment (or hoping to prop up the stock price)?
2. When insider exercises an option and then sells the stocks – is that share dilution or are those shares already factored into 'shares outstanding'? Or dilution happens as soon as option is exercised and no selling has to take place?
   ex. Elon Musk exercising options and selling – he was basically creating shares out of thin air and diluting the pool? (in his case, he was exercising for $6 and selling for $1000)
3. When shares are repurchased by the company, using company's FCF/debt – are they getting destroyed (taken out of 'float' forever) or are they not getting destroyed, instead being stored somewhere (turned into preferred shares?) to be given away as share options to insiders later on or sold on the market in the future when/if cash gets tight?