What is top speed when in electric modes?

In your car the gas engine will be forced to spin along with the electrics at about 40mph. It doesn't need to actually burn fuel, but it must spin in order to keep MG1 from overspeeding.

Plug-in models have a trick clutch that allows those versions of the car to go a lot faster before this is an issue.

 

Depends on the ICE temp and how hard you are pressing the gas pedal.

Sometimes when selecting the EV button it can kick out of that mode at 10-15 mph

Same as when taking off and not using the EV button.

But when not selecting the EV button for sure it will kick on the ICE once you get to 25 mph.

At higher speeds on the freeway I can release the gas pedal and then slightly use it again to just use the battery at over 75 mph and it will not kick the ICE on unless I press the gas pedal harder.

 

That's only in the G4 PHV, and it doesn't help with the overspeed at all - it allows MG1 to contribute power by pushing backwards without it making the engine spin backwards.

The MG1 overspeed issue was mainly 'resolved' by letting it spin faster! The MG1 reverse limit in G2 and G3 was only 6500rpm, compared to the 10000rpm it's been able to go forward since G2,and the 17000rpm MG2 can run at since G3.

 

The answer you are looking for, varies by design generation and vehicle type.

You are correct for your 2010, Liftback, non-plugin, fully warmed up (the same as I drove for 15 years). The 'v' and 'c' versions are different than Liftbacks, plug-ins are high than non-plug-ins, and Gen4+ Liftbacks are much higher than your Gen3.

I believe that for Primes, it is 80 or higher, so what "someone" told you may be correct (or at least close) for their particular year & model. My RAV4 Prime is listed as 80, though I haven't personally verified it.