We are speding 4 nights in Muerren. If we buy a Swiss Flexipass (which has been recommended), do we also need to buy the regional Berner-Oberland Pass?
I haven't heard of a Swiss Flexipass. I've heard of the General Abonnement card (everything), the 1/2 price card and some other seasonal cards. The GA card seems to be good on any train, bus, some gondolas and museums. It may cover half the price on larger gondola rides to the jungfraujoch ($134 full fare) or the shilthorn (about $80 full fare) mountaintops. Depending on how much moutaintopping or other gondola rides you plan on taking, point-to-point might work better. Looking at a Swiss rail map, it looks like the Swiss pass will get you up to Murren. You get to Murren by either gondola at Stechelberg or the gondola/train from the Lauterbrunnen train station. Cost also depends on where else you travel in Switzerland (i.e. arriving or departing). Here's a LINK to a Swiss price sheet on passes. Click on the Synoptic Map to see the train and bus runs it covers.
No, you do not need to purchase both.
Fleci Pass is the same as in other coutnries - X-number of days in a month, vs all consecutive. But if youre only in the Berner Oberland - check that specific card (will be cheaper vs whole country card). Also - the SWISS CARD will get a ticket from airport/boarder, one back, and 50% off anything else duing a month for 120-160$ or so. That may be cheaper if you do lots of smaller day trips and only 2 long trips (which are usually $100 or more easy!)