I'm not a fan of online novels. I'm just a person who likes to read novels. As for whether Blazing Teens will have a sequel, I can't give an accurate answer. It seems that there is no official announcement that there will be a sequel to this work, so I can't provide any information about it. If you want to know more about Blazing Teens: The Legend Reappears, you should go to the relevant novel websites or social media platforms to search.
In a Naruto and High School DxD fanfiction, there could be a scenario where the protagonists of both stories meet in a neutral dimension. Issei from High School DxD might be intrigued by Naruto's ninja skills and determination. Naruto, in turn, could be curious about Issei's Sacred Gear. They could start training together, sharing their knowledge and skills, and ultimately have to face a common enemy that threatens both their worlds.
If Yo - Yo was captured, it could lead to some interesting character development for the other agents. Fitz and Simmons could be pushed to develop some new gadget to help in the rescue. Daisy might be forced to confront her own fears about losing her friend and use her powers more aggressively. Also, the captured situation could be a setup by a new villain who wants to lure the rest of the team into a trap. The villain might be after the secrets of SHIELD that Yo - Yo knows.
The 'hide yo kids, hide yo wife' is a phrase from a viral video. A man named Antoine Dodson was interviewed after his sister was the victim of an attempted sexual assault. His very animated and passionate reaction in the interview, where he said things like 'Hide yo kids, hide yo wife' became extremely popular and was remixed and spread all over the internet.
One possible fanfiction could be about Naruto characters attending the school in High School DxD. For example, Naruto's positive and determined attitude might clash with the more complex social and power dynamics in the DxD world. He could make new friends or even rivals among the devils, angels, and fallen angels.
One idea could be that Ben Tennyson somehow gets transferred to the world of High School DxD. He has to keep his alien forms a secret while dealing with the devils, angels, and fallen angels in the school. Maybe his Omnitrix could be misinterpreted as some kind of powerful devil device.