A-Golem for a variety of reasons:
- You already have it at the CP limit with both charge moves unlocked
- A-Golem has more utility in having charge moves of different types
- While they're both offensively oriented, A-Golem is less so, meaning it has a higher total stat product than Electivire at the same CP
I'd consider TM'ing Stone Edge to Rock Blast for PvP use. Wild Charge is already a hard enough hitting charge move for about the same energy as Stone Edge, doubling up there seems redundant. Rock Blast can be spammed more, allowing you to eat through shields quicker.
As for fast moves, Rock Throw > Volt Switch.