I've been trying to figure out the discussion about seeds. I presume it's referring to the seed in the middle of each avocado.
Once the avocado had been disassembled and mashed the seed has nothing to do with how long the guacamole will keep. I can't imagine any scientific reason to presume it would have any effect although I'll entertain a theory if somebody will make a statement based upon science that could support that idea.
If you cut an avocado in half and don't want to use the whole thing, leave the seed in place. It will seal the part of the half avocado it covers from oxidization better than any plastic wrap. (As already mentioned.)
An avocado either whole or cut in half will keep better on your counter than in your refrigerator. If it has been cut then press plastic wrap to cover the cut surface to keep oxygen out and prevent oxidization. It seems to me that some lime or lemon juice on the surface will probably help. I don't know why refrigerators destroy avocados but my personal experience is that cold ruins them. Better off to leave them on your counter. I'll be interested in a scientific reason why refrigerator chill ruins avocados.
It's pointless to speculate how to best keep guacamole. That has happened, what, two maybe three times since the dawn of history?
You don't need to keep it unless you made enough for an army and invited only 2-3 people. Barring a dreadful miscalculation like that, guacamole evaporates as long as there is sufficient supply of tortilla strips, chips, crackers, bread, etc.
You can grow an interesting plant from the seed taken out of an avocado. Stick three toothpicks equally spaced along the "equator" of the seed, sticking out perpendicularly. (Three has the same stability as a tripod--you can use 4 toothpicks if you wish.) Place the toothpicked avocado seed in a small dish such that the toothpicks balance the seed in the middle and supporting it via the toothpicks on the rim. I believe the stem end should face down because I recall that's where the roots want to grow from. (Let me know if I have this wrong. Maybe it doesn't even matter.) Add water to cover the bottom part of the seed, and keep adding water every day to replace any that has evaporated. Place it near a window, in my case usually in the kitchen. Given a few or several weeks it will grow into an interesting vine. You can mix some plant fertilizer in the water you add to keep it growing. It always amazes me that so much vine can keep growing from a relatively small seed with not much nourishment, if any. You can probably transplant it outside if your climate suits and it will probably grow into a bush or tree.
Well I've been snacking on guacamole as I type this and I see I'm almost out of guacamole, so I've probably typed enough too.