HoT: 10 HP-regen is nothing to joke about, it would be the highest raw HP-regen in-game. I'm actually not sure about this. The 40 STR already grant 1.2 bonus HP regen in-battle by itself. I personally think 10 HP-regen in-battle is often not worth as much as 1% HP-regen outside of battle.
Currently, the meta-game is mainly full of nukes and burst damage. If enemies focus you and you're not dead after 4 seconds, then it's already obvious that they're on the loosing side. But within 4 seconds, this regen is useless. It's only really useful if the battle goes on for at least 25 seconds, which is a lot.
The 1% HP-regen and 40 STR are far more useful. They can grant you enough HP to survive the first bursts and get out of the centre in time. After that, you could get out of the battle. With the high HP-regen outside of battle, you could even make your come-back if the battle still drags on or goes into chasing.
So currently, I would simply say that 1% HP-regen outside of battle is way more useful than the 10 HP-regen in-battle.
With Bloodstone it's kind of similar. You'd have to nerf its MP-regen and I personally find the high MP-regen much more useful than a high HP-regen due to reasons explained before. It could easily become overkill or too nerfed.
Meka is different, because it's a burst heal and can as such easily safe lives. It's relatively powerful early-game, because a 250 HP heal means a lot. With this change, Mekansm could have an even stronger impact on the outcome of a game, because 400 HP healed and +5 armor is just an immense bonus.
However, I would say it's rather balanced this time. Looking at the price and at which heroes get Mekansm, there's only few which would actually farm that much gold (special mention Necro).
I like the idea, but it could easily become oped or not level upped at all, so it needs to be worked out carefully. TUp for concept