How do you gain HP?

Unknown

When events are running concurrently with LRs, sure. Its a nice easy way to get up to 200 tokens for the week.
Or you know, you could just place in tourneys for the hp. Unless you are still using a ** team, then just sell off that yelena or bagman for a slot. With the pve events and the change in sell price to pure iso, you'll get 141 easily. I think if i remember just brotherhood alone by playing everything with the other tourneys netted me 150k in iso. Thats like 20k more and I can max a guy from start to 141, a far cry from the months and months people have been complaining about the time it takes to max a ***.
30 days or so to max 3 141s, as long as you have the covers, which people aren't lacking most of the time. I expect in 2 weeks time we'll have many many 141 hulks walking around in tourneys, then once spidey nerf, I'd like to see you earn hp then compared to now