I have written two STEM papers (Paper1 and Paper2) and I have already submitted Paper1. Paper2 implements some of the methods presented in Paper1. The conference I submitted for Paper1 and the journal considered for Paper2 both require novel work and state that the work presented in the paper is not published or under review by other journals. Both the conference and the journal are prestigious and Q1.
Paper2 is more of an expansion of the first with more methods, data and discussion. So, what are my options for Paper2 now? I am thinking of one of those:
1- Rewrite the methods of the first paper but with different phrasing than what was shown in the first paper. I think this falls under "Not under review by other journals".
2- Option1 but without mentioning that the method is novel and try to make the writing as short as possible so Paper1 is the complete version.
3- Wait for the first paper to be published then reference it and summarize the methods. The problem with this option is that the conference will be in October and the paper will be published in Decemeber, and I cannot afford to wait ~9 months.
Is there an option I am missing?