Cleaning house

I'm trying, TRYING, to go through Kittyboy's toys and post what he really doesn't play with on Freecycle. I've done this a few times, once when we realized that he just wasn't a stuffed animal person and we gave away most of those, and another time when I was just fed up with the amount of toys we had. We gave him a teddy bear for Christmas (it was wearing a sweater, I couldn't resist) and a book for his birthday, chipped in with the great-grands on a bunch of plastic farm animals, and that was it - then the extended families' gifts came out. He has probably twice the amount of toys he had before, not that any one person gave him a WHOLE bunch (though several are big), but more that everyone altogether just gave him soooo much. Naturally, I'm anxious to clean out from what he got last year. But what has to go? The little blue teddy bear some friends gave us while I was in the hospital with him, that's special because of the time and because I know they didn't have money at the time whatsoever. He doesn't play with it, but it's still special. The wooden blocks he doesn't play with, I know he'll play with one day, and future children will play with them. He's got a whole big box of them, you don't give away basics like that. We've already passed off stuff he didn't play with often to other houses where he spends time - my parents, Husband's parents, an uncle's - and found out that the in-laws take it personally if anything they gave him comes back, regardless of whether it was given for an occasion or just something they saw and picked up because he "might like it". And then there are the vintage Fisher Price toys out in the garage - they aren't in the best of shape, but they're things Husband and I remember playing with when we were little. We can't get rid of THOSE.
He has the pint-size ATV, an un-motorized ride-on toy, one of those big red and yellow Fisher Price cars (he can't figure out how it works, but the in-laws would be insulted if we offered to bring it back to their house for him to play with when he visits there - and IT'S HUGE, so if they visit and it's not here, they'll notice), and two big Radio Flyer wagons. One is in pretty good shape and is from, again, the in-laws, and one needs some fixing up but I looooove it because it's a bit of an antique and well worth fixing up. He has a rocking horse, and a rocking caterpillar. Caterpillars, my gosh, he's got a three-foot and a SIX-foot one the trucking uncle picked up at a truck stop somewhere - couldn't decide which Kittyboy would like, so he got both.
Then there's also the fact that we will at some point have more children!
So... any suggestions? Here's what I've come up with thus far:
1. Take inventory of toys at Other Houses - get rid of anything I don't remember, or which has lost sentimental value in the months that we didn't miss it.
2. Anything easily and cheaply replaced at a dollar store or Walmart. If the replacement value is under $5 (maybe $10), it's not worth the "cost" of storage.
3. Take things that aren't often played with to the Other Houses to replace those which were gotten rid of (see #1).
4. Inventory the vintage Fisher Price, and find out if anyone on Freecycle collects such things - if we really, really want the little plastic record player, we can buy one off of Ebay sometime that actually works well.
5. YOUR SUGGESTION HERE.

Seriously, input would be great.