Expensive characters at small point values are a trap, unless they're something that can table the opponent by themselves like Beastclaw stuff. One hero is enough for us Stormcast at that level (other armies that rely on combos such as Bloodbound are different). The exception is something cheap like the Lord Relictor.

I think for that point level the Lord Celestant on Dracoth is enough hitting power, probably drop the Knight-Venator. You'll also have to be careful with the Dracoth hero since he'll get separated by speed really quickly.

Honestly the best Stormcast build for that point level (imo) is something like this:

Spoiler
Show
LC on Dracoth
Judicators
Judicators
Prosecutors with Javelins
Prosecutors with Javelins
700


Where your Lord Celestant just runs around smashing faces while everything else jumps around in back doing damage from a range (which they're quite good at). If you want to run more punchy dudes you probably want something like this:

Spoiler
Show
Lord Celestant
Liberators
Liberators
Protectors
Retributors
720


Note that this list is slow as crap, but anything you reach you should either tie up with Libs or obliterate with everything else. Lord Celestant's +1 to hit bubble makes the Retributors deal 2MWs on 5+ to hit which is nuts, and the Protectors can help a reasonable amount against shooty lists with their -1 to hit.

At low point levels (aka 1000 or less) you need every unit to work well together. I feel like your lists were a bit scattered - Liberators want to tie up things but were too slow to keep up with the LC on Dracoth and the Venator is quick and ranged enough to not need bodyguards at most times. Celestant-Prime is probably too expensive for a pure SE army at 740.