What is the best path to take for sif
Defense and HP path to increase her survivability seems best to me.
As she is a counterattack hero I would go HP > Def > Attack
Less Def = more counterattack (but 1 Def ~= 2HP in terms of damage taken)
It depends on where you will use Sif.
I took my Sif all attack because I wanted her for Titans, 916 attack stat and she protects the Jackals. In addition she holds up well in most raid situations with this emblem path even in this less robust build.
If you are using her on defense, the more defensively you go the better she will defend your stronghold.
I have her on my SH defense as the tank in reverse double and the cups are enough that I have decided not to reset emblems. My logic is that since the only person harmed if she isn’t optimized for defense is me, and I am not really sure there is any harm (resetting was under heavy consideration) AND Titans remain important to me.
If you will use her on War Defense then you really should go all Def/HP out of respect for your alliance mates!