Thing is Saints types, I don't think you are a million miles away from getting back on the horse.
Saints' primary problem is being easy to read/control in attack. Virtually all sides now play with their fullback as an additional ball handler/attacker popping up either side of the PTB making defences guess/stretch to counter this. With Saints attacking from around marker/first receiver it is easier to concentrate defences around that area to suffocate the attack. The loss of Graham and his ability to draw players in whilst tipping the ball on has also compounded this.
If Roby gets a roll on from dummy half he will still hurt the opposition, control it, and he is pretty damn nullified. Lomax too, can be got at due to him being your only playmaker and standing close to the PTB at first receiver. Hohaia at stand-off is purely wasteful, give him space/broken defences and his footwork and speed will be a far greater asset.
My two'penneth: Hohaia to fullback, where he appears to have played for NZ/Warriors for the past three years (reasons as above); Wellens to loose forward, his experience and pretty decent passing game would give Lomax some much needed support in the middle of the pitch, a variation on Sinfield, if you will. I think his defensive contribution would also lighten the load on Roby, keeping him fresher in attack. Finally; Gaskell (possibly Wilkin) in at stand-off. It would give a little more control/organisation to the side and leesen the responsibilty on Lomax, who appears to be tasked to do everything.
This is obviously a short term solution, as I I think any side would struggle bringing two young halfbacks through together. I certainly think you need to bring in an experienced halfback next season to aid the development of Lomax/Gaskell.