1 - An additional $500 chip is added to the "pot"? Does this mean you have a round where for every hand [on every table?] a $500 chip is added to the pot? Or are you adding money to the total tournament pot (the prize pool)?
2 - Create a bounty prize on the previous winner. The prize can have an award of type "non-monetary". Adding a chip to the tournament doesn't really affect anything... unless you're concerned that the Total Chips / Stack count will be off, in which case you can add a rebuy for the recipient which cost them $0 and they get $500 in chips, or simply adjust the total chip count (on the Game tab).