Do event Pokémon have EV points

Looking through the Bulbapedia learnset entries for each HM move, I have found no instances within each HM set where a Pokemon learn it, but its evolution can not;

1. Cut (HM01)
   • Diglett/Dugtrio can learn Cut in Yellow, but not in R/B
2. Fly (HM02)*
3. Surf (HM03)*
4. Strength (HM04)
5. Flash (HM05 Gen 1-3)
   • Venonat/Venomoth can to learn Flash in Yellow, but not in R/B. Venonat loses the ability to learn flash in Gen 2
   • Hoothoot/Noctowl lose the ability to learn Flash in Gen 4, although it's no longer an HM.
6. Defog (HM05 D/P/Pt)
7. Whirlpool (HM05 Hg/Ss - HM06 Gen 2)
8. Waterfall (HM05 Gen 5 - HM07 Gen 2-4)
9. Rock Smash (HM06 Gen 3-4)
10. Dive (HM06 Gen 5 - HM08 Gen 3)
11. Rock Climb (HM08 Gen 4)

There are a few fringe cases that pop up in earlier generations (Mostly between Red Blue and Yellow) where a Pokemon might learn the HM in one game and then be traded to another where its evolution cannot. There may also be unmentioned cases of this between Gens 1 and 2, however the Time Capsule was fairly restrictive in what could be sent back.

*Pikachu is an interesting side case - As there are event and side-game transfers that can give you a Pikachu with Fly, or even Surf (there's also a surfing Pichu). However in none of these instances can Pikachu be taught the moves from an HM.

I had a play with a damage calculator I found online and my conclusion is: there are way too many variables to produce a definitive answer: base stats, IVs and Nature all play a part, even at level 5.

If your Pokemon has perfect IVs and beneficial Nature and your opponent has 0 IVs and negative Nature, it looks like you could deal at least an extra 20% damage than if those stats were reversed. I tried a good Snivy against a bad Tepig and got 42% damage from using Tackle, whereas a bad Oshawott against a good Snivy only did 14% damage with Tackle.

In my experience, using any status move is not worthwhile. It always takes the same number of moves before your opponent is KO'd. Example: assume an average damage of 20%, that would normally take 5 Tackles to KO your opponent. If you used Leer first, Tackle would deal ~30% damage (20*1.5). Now it takes Leer + 4 Tackles, so you don't gain anything.

Also note that your opponent uses moves randomly, which you can benefit from: Tackle>Leer>Tackle always does less total damage than Leer>Tackle>Tackle.

My advice: never use more than one status move, and if you do use one always use it as the first move. Then just spam Tackle.