The issue I see for you is that if you don't respond to the text from your bank/CC company to approve an activity, they may lock your card.
So, I would contact each bank and let them know you will be out of the country and for how long. That should minimize the verifications needed. You can tell them you will not be able to receive texts during that period.
As for cell service, most providers offer an international rate.
ATT offers a $10 for 24 hour period "day pass". You only pay if you use it. So, if you call/text family back home on Monday at 7 am, you pay $10. Every other call/text you make from then until Tuesday at 6:59 am will be free. Once, if, you hit ten days of use during the same billing cycle, you will not be charged for any additional days within that billing cycle.
I did this, and to minimize the days paid, I put the phone on airplane mode for the bulk of my trip. Every few days, I would turn off airplane mode and check for messages (text, email and voice). Over the next 24 hours, I would send messages, make calls home, internet surf, etc. Then I'd turn on airplane mode again.