Are there any differences between legato scale technique on acoustic guitar, and how it is explained in this video for electric guitar?
I don't think there is any more difference between an electric and an acoustic guitar for hammer-on/pull-offs, than there is between two different acoustics, or two different electrics.
The action, the string guage, thus the string tension, all affect exactly how h/o and p/o are executed: some guitars will need a harder h/o and a stronger p/o, others lend themselves to the opposite. Low action with thinner strings is probably the best combination - which could occur on any guitar. Having said that, acoustics often come equipped with heavier strings and higher action - but some players prefer that on electrics anyway.