I don't know if it has been explicitly stated here in the past, but confirmed by a banker on the business side that the minimum credit limit for the NAF Chase biz cards is 3k for sole proprietor applications.
in addition, the in branch application for SP business checking with bonus is not nearly as scary as the other internets make it seem. Go for it
Several DPs are between 3k-5k. It is good that you got confirmation on the lower limit.
Both cards grow over time. The main issue in the first months is spending 6k to get the SUB, while having only a 3k CL 
Fico8: EX~EQ~TU~840 (12 month goal~850).