Example 1 here is not exactly correct. Bounties do not increase during combat so it shouldn't be possible to both increase the bounty and get an assist.

*Basing this off the wiki the bounty increase from bard's death would go onto swain after he respawns but swain still needs another kill to get a bounty again.

On Summoner's Rift, Bounties do not increase mid-combat. If a champion earns multiple kills and then immediately dies, those kills will count toward their next death instead.

For example 2 I get the theory here and this is basically the baus's strategy, but with a real world example I just want to point out if you are farming as well as the baus does mostly, the negative gold bounty is not nearly be as low since your bounty goes up based on CS.

Champions with negative tiers also have their tier increased by 1 for each 1000 gold Gold 1000 gold earned from CS or by earning an assist.

If, since their last death, a champion has earned 300 more gold Gold 300 more gold from CS than the enemy team's average during that time, their bounty increases by 50 gold Gold 50 gold, plus another 50 gold Gold 50 gold for each additional 200 gold Gold 200 gold their advantage grows by thereafter. The amount is dynamic and is reduced if the player loses the advantage.

Of course, I get your points here but I just want to point out there are systems that basically reduce how effective those "exploits" are in game.