Correct on the use of the 70% rule and ALWAYS run with conservative numbers - if the deal still works then you'll be in good shape when something goes off-target (e.g., appraisal). On offer price, realtors don't always have a great understanding of investing metrics (I say this as a realtor myself) so take their guidance on offer with a grain of salt, but at the same time they should know your current market well enough to understand if an offer less than ask even stands a chance. My mindset on this is I wouldn't worry what other people are offering - make the offer at the highest price that still makes sense for you and if they don't take it, on to the next.
I did a BRRR deal with extremely similar numbers and it worked out great (initially i was going to flip it but it made for a great rental property. Also a benefit if you decide to live after the rehab is getting a better LTV% from the bank on a primary (be wary of a 6 month seasoning period from lenders on cash-out refis) and locking in a lower (primray) interest rate which will help with cash flow once you rent it out (although with rates so high this aspect is less attractive at the moment).
Good luck!