1) An investigator has the .45 Automatic (+3 STR), and the Wither Spell (+3 to STR suring Combat). Another investigator has the Intervene Spell (+3 to Combat of another investigator).No. You're limited to a single +X bonus per combat.
Can the three bonuses stack for the first investigator when making a Combat Encounter?
Anything else on the cards (rerolls, ability to boost dice, rolling "additional dice", 6's counting double) does stack.
2) Patrice's passive is: "When you close a Gate during an Other World Encounter, gain 1 Clue and 1 Focus".I didn't quite follow that.
Does this apply when she performs an Other World Encounter, "closes the Gate" as per the card's effect, but doesn't actually close a Gate because the encounter is for something else (Rumor, Mystery, etc...)?
Let me see if I can break it down for you a bit better. Her ability works during an other world encounter only. That means, you have to draw one of the cards with the gate symbol on the back. If you close a gate any other way, it doesn't count for her ability.
If, as a result of that card, you remove a gate marker from the board, you have closed the gate. If you're prevented from actually removing the marker because of a rumor in play, it doesn't count. If you put the gate marker somewhere other than the discard pile, it still counts, so long as it leaves the board.
If you're drawing an other world card for some reason other than you are standing on a gate (rumor, mystery, returning from LiTaS, etc.) it doesn't change the premise: if there is a gate token removed from the board as a result of the card, it counts for her ability. If you don't remove a gate, it doesn't.
3) Let's say a game started with 6 investigators. The Ancient One woke up (so no new investigators come up when the other are defeated/devoured). No.
At some point, 2 investigators die, leaving 4 in play. Does this change the "number of investigators", thus changing the goals of mysteries, rumors, epic monsters?
4) Can you gain a Bank Loan to move to the Miskatonic Outpost?Yes.