2 conventional loans at same time - same or different lenders?

[Kosh Vokter]

Need to apply for 2 conventional loans for 2 different investment properties that are in different states. It just so happened that the 2nd offer got accepted and have enough cash for 20% down-payment for both including some reserves. I have an existing contact and pre-approved with a national bank . I would like to apply and work with a local lender for the 2nd property and loan, to build a relationship with another lender besides the national bank and who my realtor also prefers working with (my realtor is not forcing me to work with the local lender though). I am not sure if the local lender can do simultaneous loans and this is my 1st loan with them. I have done loans with the national bank before but they might not have the best terms. 

Is it advisable to work with the same lender for both the loans?

Besides experience closing 2 loans at the same time, what are the things that you ask both the lenders upfront to help me decide if I should go with different lenders or chose the same lender for both?

I know I have to disclose both the contracts/loans with both the lenders (if I go with 2 different lenders), is it also necessary that I disclose that information with both the realtors? I know it won't affect the loan process, but is it required or courtesy to let them know.