It seems you can find some or maybe all of the items just by searching, but I'm so poor at that I've really only found the rope and 1 of the 3 bombs you need. I can see places you need the stick, the rope with hook, and the tent, but can't find them there. The places I'm stuck at is how to unlock the first door to the naked prisoner(the door to the cage is already open), the thief guard who tells you you have to be a thief to pass, the door in the stealth corridor that says it needs the "warehouse key" (but I already have a warehouse key), 2 of 3 bombs, and how to convince the priest who chastised me to... proceed. Any walkthroughs?
There are a good chunk of items you cannot obtain in the thieves' hideout. Instead, you're supposed to order them from the base camp by picking the second option from the top when talking to Commander Derio. The items listed from top to bottom are: a tent, a bomb, a hook with rope, an HP restoration item, sake, a stick, a rubber boat, and an MP restoration item. You can order up to three items at a time, and you must wait four days for the shipment to arrive. You have to make sure you enter your cabin on the fourth day (go to sleep there on the third day and you'll receive it on the start of the next day, for example) otherwise your shipment will be lost. If your relationship with the commander is high enough (joined him in the bathhouse a couple of times), the wait time can be reduced to two days.
Based on my experience, you will need two hooks with rope to fully explore the underground temple. The temple will also provide you with a couple of bombs, should you need them.
Using the stick will earn you an amulet that you can wear to seduce the priest who chastised you. You can also use the amulet found at the bottom of the temple for this. Simply speak to him while equipping it. After having sex with him you can gather everyone once more which will then trigger another line of events.
The tent doesn't really do anything useful from what I've gathered. It just gives you a free place to rest outside of base.
I have not been able to open that prisoner's door either. I had managed to trigger an event with her in an earlier version of the game where the tunnels were bugged, but I'm plumb out of ideas for any legitimate methods.
I'm not sure which thief guard you're talking about, honestly. If you mean the guard next to the massive mansion, you just need to continue the priest questline. You will be offered a job there after completing it. If you mean the guard next to the warehouse with destructible crates, you will need to get him a compress by going to the thieves' HQ's warehouse. To get access to *that* you will need a key, but I forget where you're supposed to get that. I think you can get it from following Doggy's (the prisoner thief you meet very early in game) second or third bit of info.
The second bit of info allows you to search some toilets, and the third allows you to get a gun that can defeat the thief boss from behind as long as you stay in stealth mode. You can get a fourth bit of info from him that hints at a beach area. You can get the key for said beach area by talking to the cow farmer after you've collected enough info on it. You may need to deliver a rough diamond to the writer at the southernmost house of the residential area, where the guy waiting for the barrel and the little girl that wants to go to the toilet are.
