From the regs:
p10
"The catch limit is the number of fish you are allowed to catch and keep in one day and includes fish that are not immediately released and any fish eaten or given away. The possession limit is the number you are allowed to have in your possession on hand, in cold storage, in transit, or anywhere. Possession limits are the same as one day’s catch limit except where otherwise specified. If you catch a fish after reaching the daily catch or possession limit for that species, the fish must be released immediately. If the limit is zero, anglers may practice catch and release only, and any fish caught must be released immediately."
Doesn't leave much room for interpretation, but rules around gifting are not well explained. Any fish you give away are not part of your possession limit, and you can give away fish (within provincial possession limits) to people with no licence or with a conservation licence. Based on that, I would think that a two person household (for instance) should reasonably be permitted to possess two legally-caught limits of walleye, regardless of who caught them, on the basis that the food is shared in the household (half of any fish I bring home for consumption could reasonably be presumed to be gifted to my wife). Certainly this would be allowed if I gave the fish to someone outside my household, so the same should be true for wife, kids....everyone gets a limit. Just my opinion though, please correct if I'm wrong.
As for bass holding limits and tournaments, the exemption is on p14 - anglers may catch, hold, and selectively live release more than a daily limit of bass provided that no more than 6 LM and SM bass (combined) are held at any one time for fish caught under a sport fishing licence. Note that the regs specifically state "6" for bass, not referencing zone-specific limits as they do for walleye and pike. So if the bass sport limit is 4, you can still hold (and later release) up to 6 provided you meet livewell requirements and size restrictions (if applicable). Refer to regs for full details. Don't try it with walleye or pike - you can selectively hold and then live release as many as you want, but may not at any time hold more than your daily catch limit.