Hello guys,
My parents are taking MAA- IAH flight via Changi and DME.

Have some questions for you experts.

SQ62 Singapore - IAH via DME.

From what I have read, it seems you have to get down at DME and clear security and reboard. Is that right?any issues here? things to pay special attention?

IAH - MCI via memphis is the connection
The flight is supposed to arrive at IAH at 2:05 pm.
What terminal does this arrive at?

Is there a delta baggage drop off after customs and how far is it?
The connecting flight to Memphis is at 4:30pm

What is the quickest way to get to terminal A after baggage claim?
Is there security check again?
Also, the tickets were booked by me via Master card secure code system.
Do they still need a LOI? I am getting conflicting info from their customer serivce

My parents are 60+ and so detailed instructions will help them navigate easily.
Thanks a lot for your expert advice