#2 (the arcs based on the final SATCOM reading) would have to be
radically wrong for the Maldives sighting to be a genuine MH370 sighting, or for the straight-west-until-the-end theory to be correct at all. I suppose it's possible that someone got the calculation based on signal strength (or was it latency?) horribly wrong, but wow what a big clanger it would be.
(The Maldives report and SATCOM conflict under any theory of the incident, btw: a 777 simply can't cover the distance from any point on the arcs to the Maldives in an hour.)
For perspective, it seems there are now reported could-have-been-MH370 sightings more or less wherever you want them in the region, such as as south and east of where the transponders were switched off: http://www.countercurrents.org/jkp180314.htm .
Oh, and speaking of eyewitness reports, IIRC the Thai authorities don't believe that MH370 ever entered Thailand (based on their radar data). It's hard to draw a straight line from just south of Thailand to the Maldives without clipping southern Sri Lanka or western Malaysia around Aceh.
#1 is easier to try to knock down, at least partly. One aircraft could be mistaken for another, the readings must have margins of error, and it's not clear that the charts showing a VAMPI -> GIVAL -> IGREX path for the aircraft aren't based on reading something into the radar data which isn't fully supported there. OTOH, supposedly the radar traces attributed to MH370 were verified against the SATCOM readings, though I can't find a good source for that so caveat emptor.