Clark and Tal are somehow able to have a conversation while floating near the sun. There is no atmosphere in space to carry sound waves.
Even if Superman were able to survive a trip into the sun, his suit and cape would not. They have been shown throughout the series to not be invulnerable, repeatedly received rips, tears, and burns.
Tal flies Clark into space and into the sun and somehow survives in the vacuum despite being powerless.
When Lois goes to see the two Allys in their cell at the DOD, she is initially unable to understand Bizarro-Ally's backwards speech. However, during their conversation, Bizarro-Ally interjects a few words and Lois is able to understand despite the speech still being backwards.
It was not explained what happened to the people of one of the two Earths that were on the other Earth at the time Superman stopped the merger from taking place. For instance, Lois of Earth-1 was on Htrae at that time, how did she get back to Earth-1, and Htrae's Lois Lane was on Earth-1, what happened to her? Similarly, the DOD had earlier nabbed Htrae's Jonathan and Lana and they were in custody on Earth-1, what happened to them? Did both planets identify and take their own inhabitants back somehow? If so, how did the Ally from Htrae remain on Earth-1 as a prisoner?
John and Natalie transfer all their suits' available power to the pod to disrupt the portals, yet they have power to their communication systems to keep conversing with one another and later are able to fly out of the portal and back to the Kent farm.
Clark believes that Tal throwing him into the sun will jump-start his powers and level him up to the degree needed to take on Ally. This plan is not only highly dangerous but ignores the more obvious solution of having Tal fly into the sun to level up. Tal's cells are functioning normally and absorbing solar radiation as they should, unlike Clark's, which require a risky attempt at restoration.
The Smallville firefighters ask Lana what they should do, and she tells them that they've done all they can and the most important thing is for them to go be with their families. The city is being plagued with accidents and emergencies brought on by the merging of the two worlds (Lana and her daughters just witnessed a car accident as a result of a driver disappearing from behind the wheel of a van that arrived from the other Earth). As first responders, the fire department should be attending to emergencies, not going home to spend time with their families.