Short answer for accuracy is that we don’t know yet. To my knowledge no one has done a ground-truth-based accuracy test (using something like GPS Benchmark — https://play.google.com/store/apps/details?id=com.gpsbenchmark.android) that would tell us what the real accuracy is.
The current firmware reports two signal records for some satellites that are both indicated as “used in fix”, so presumably each of these records is a different carrier frequency. This would mean that it is indeed using more than one carrier frequency when computing a position. It doesn’t report the actual carrier frequency of those signals, so we can’t explicitly confirm that one is L1 and the other is L5.