What weapon loadout do BoP users use at T5? I am unsure of what weapon types I should throw in the Front 4 weapons slots.

A turret in the front? really? We are talking about the BoP here it has an almost OP turn rate why would you waste a fore weapon slot like that?
You must be trollin'.

Anyway try this:
Front: 4x DHCs
Rear: 2x Turrets

Use two copies of RF an attack pattern and a tac team... save the rest of the slots for heals and such.

Classic approach to the T4 Hegh'ta or T5 B'rel-R,

(2) DHCs
(1) torp
(1) DBB

Use BO3 + DBB for the spike to shields (with full Tac buffs)
The DHCs keep constant pressure when boosted by CRF
and the Torpedo for the killing blow.

Turrets in back

I'm usually going with

1 dual heavy cannon (dis)

2 dual cannons (dis)

1 Quantum torpedo

2 turrets in the back.

I see no point in a dual beam bank, just lowers the damage of my rapid fire III and the debuffs from ATP Beta.

Posting in a Zombie thread
My torpedo Brel Build.
fore=1x Quantum torps, , Bio neural warhead,, Breen cluster mine torpedo, peng,
Rear,= Chron torp, Tricobalt torp.
good times.

It's all about spike damage. Even if you lose damage from your CRF, you gain a lot for your spike with a Beam Overload 3.

It may be debatable (not in the sense of Tier 2.5-ship-being-overpowered-debetable, I mean real debatable) whether it's still better to stick with only one burst weapon (DBB or Quantums), which one would be better, or if it's best to mix 2 burst weapons with DHCs.

This is how I roll. The dual beam bank helps really spike up the alpha strike damage when boosted by Beam Overload. Of course, you have to trade out cannon-modifying consoles for energy-type-modifying ones (I run with all AP weps) to get the full benefit.

Sometimes I trade out one rear turret for a torpedo; either a photon/quantum for boostable damage or a trico for an in-yr-FACE goodbye as I pass by.

I have no idea, honestly. If so then a better build is possible as one could try.

TT1 CRF1 BO3 ApB3
ET1 EPTS2 EPTS3
HE1 TSS2
THY1 CRF1

Offering better survivability though the TT1 would have conflict with the ET1, but only for 15 seconds at a time.

Of course one could switch it to be;

TT1 ApB1 BO3 CRF3
ET1 EPTS2 EPTS3
HE1 TSS2
THY1 CRF1 Of course teh ApB1 is optional and you could run something else there.

1 Heavy and 1 Normal Dual or both Normal Dual Cannons?