No. Micromax Canvas 1 does not have any heating issue.
Yes, Micromax Canvas 1 comes with a dedicated memory card and you can expand phone memory by another 32GB with the help of the MicroSD card.
Yes, since Micromax Canvas 1 runs on the latest Android 7.0 OS - there is multi windows support.
Yes, Micromax Canvas 1 is a dual sim mobile phone.
Yes, Micromax Canvas C1 does have the wi-fi hotspot function.