If I had been Angel, the first thing I would have done would be to recruit more help. The first ones who come to mind are Gwen and Gunn's old crew, but over 5 years, Angel must have come across a few trustworthy people/things who would have been willing to help stop Wolfram & Hart take over the world, either because it was the right thing to do, or simply to protect their own turf from invasion by another, much stronger, "gang."
Secondly, wherever possible, I would have assured that NOBODY went in alone. Hamilton was obviously the most powerful, so a coordinated attack on him would have been the first priority (Connor's showing up when he did was the only thing that saved Angel and gave him the chance to get the job done, and even then it was sheer luck in the form of Hamilton's "You cant stop us, we are Legion..." boast that won the day. Alone, Angel would have been dust long before that point). Angel facing him alone was sheer ego and bravado. Even as only a distraction, a few extra people would have helped. Okay, they might have been killed, but remember, Angel told his own crew that few, if any, of them would survive the night, so the whole thing was a suicide mission to begin with.
Then, I would have had Illyria accompany Wesley in the first place to take out the wizard, even if it meant having her wait outside until she heard the fight start, then crashing in to back Wesley up. Better yet, have HER appear to betray the others and give Wes the opportunity to come in with some serious weaponry, not just an ineffective fire ball spell ( this is a wizard capable of manipulating time, for pity's sake, you can't expect a mere human to be any match for him.) and a sleeve knife.
Having Spike rescue the baby was practically a given, as that was a one man job, requiring the rescuer to face an entire room full of demons literally single handedly while holding the baby in the other. He was the single best fighter of the group, and had the best chance of getting the job done with any degree of success.
Gunn would have one or more of his crew as back up taking out the Senator and her staff, because that was, once again, not a one man job, and his friends had plenty of experience taking out vampires.
Most of the rest of Gunn's crew would take out the limo full of demons using their assault weapons, explosives, flame throwers, whatever the job took. Whoever furnished them with their automatic weapons could have provided heavier firepower just as easily as Uzis and Mac-10's, and I would be really surprised if the gang didn't already have at least grenades in addition to their guns. If not, fire bombs and privative explosives are easier to fabricate from household chemicals than you might imagine, and, given their line of work, they were probably well aware of it.
Lindsey and Lorne could have used at least one armed man as back up, but even if they had gone in alone as planned, killing Lindsey at that point was a tactical mistake, simply because, and Angel KNEW this in advance, everyone left standing would be required in the alley to face whatever force that the Senior Partners would use in retaliation to his attack, and even then the chances of survival would be highly unlikely. If they had survived the battle, there would have been plenty of time to take care of Lindsey later, well before he could initiate any plan to betray the others (while we're on this subject, Lorne's "high note from MacArthur Park" would have been quite useful in the alley later, as well, and would have required very little in the way of further involvement in the fight afterwards).
And before anyone says that there wasn't time to set all of that up in one episode, "The Girl In Question" was a total waste of time, and should never have been made once it became obvious that Sarah would not be appearing in it. That would have given another hour to make "Not Fade Away" a two part episode, and it could STILL have ended the same way that it finally did, only with a few more able bodied fighters standing beside Angel in the alley.
