Third evolutions have higher IVs?

Nah, the Charizard, Gengar and both Blastoises I've caught have all had bad IVs

Plus generally speaking the 3rd evos I have caught (other Gengar, Pidgeots, Victreebell) have all had pretty poor IVs with the exception of a lv 2 Poliwrath I caught which was in the 60-80% range

Congrats! I have yet encoutered either lapras or chaizards since day one.

Btw, were you using incenses during those catches?

I'd say the sample size is small enough to make up for all the low IV wild catches I've had lately. If that lvl 30 with 87% IV Charizard has WA + FT/FB, you've really had some great luck with that one.

Out of the 6 Lapras I've caught since I started playing, the two best ones had 55% and 60% IV. The rest were sub 40's. By your reasoning, that would conclude rare wild catches always have bad IVs, which would also be wrong to assume.

Most wild mons I catch have crap IVs. Never seen a wild Lapras only hatched one. I've never seen a wild 3rd generation starter, but I have seen a few 2nd gen.
I have never caught a wild charmander or wild bulbasaur with IV >90%. Wild squirtle are exceedingly uncommon where I am.

You are very lucky. I have never seen a high IV 3rd evolution except one time a 87 poliwrath.

I've caught 15 snorlax only one had 84% all other one were below 68

I caught two Venusaurs and a Blastoise yesterday, and two are in the <50% IV category, and the other is in the 50-66% category (just going by the in-game appraisal; I haven't actually run them through a calculator yet).

I did catch a lvl 30, 77% IV IS/B Lapras on the first day the Santa Pikachus came out, and the first wild Lapras I ever caught had 88% IV's with FB/B, but it was low-level (CP 490).

I'm pretty sure the IV's are random.

I caught a 1900-ish CP 100% IV Venusaur yesterday, pretty sweet.