Interestingly, if the number of participants in the airdrop is less than 20 thousand, will all the tokens be distributed?
You mean are distributed between those who take part in the airdrop?
I do not think that all tokens will be distributed, most likely the maximum for a given airdrop is 5 tokens per participant.
In the conditions it is written: 100 000 tokens for 20 000 participants. There's no information about 5 tokens for one participant.