Using 'Big Banks' for a mortgage loan?

[Adam Juodis]

I've heard heard/read often that for a conventional loan, people should go to the local community banks around their neighborhood. I was wondering if I should even bother with a bank like Chase to get funding for a future REI? I have many different accounts open and a good relationship with Chase, so I was thinking that could potentially help me out. I know that after having a mortgage on so many properties, conventional loans are not an option, but I have yet to buy my first property.

I was also wondering, if I got pre-approved for funding, say, today, how long of a grace period do I have before the option to take the loan disappears(This probably varies per loan..). My goal is to purchase my first REI by Spring next year, but if a good enough deal comes around, I want to have my funding ready. I want to make sure I don't waste a hard pull on my credit for no reason!

Just trying to educate myself a bit more on loans, so I don't make a fool out of myself when I go in for talks. Thank you!