In situations when you're up against multiple loose opponents (and profitable bluffing opportunities diminish), how much do you tend to tighten up your iso and open raising ranges?

I'll give you a couple of old situations I remember:

Scenario 1:
Let's assume 1/3 stakes and 100bb eff stacks for every scenario
EP young guy limps
Hero in HJ raises to $15 KTo with two loose players who have position

KTo crushes young guy's range as he's not the OMC limp-raisey type, he would open good hands himself most of the time. The two players behind are most likely playing 30-40% of hands. 40% of hands looks something like
[TT-22,AQs-A2s,K2s+,Q6s+,J6s+,T6s+,96s+,85s+,74s+,64s+,54s,43 s,AQo-A2o,K9o+,Q9o+,J9o+,T9o,98o,87o], although they could be even wider. In this configuration, every player has around 25% equity. I probably want more equity than that given I'm out of position to two players, no? Fwiw KTs has 28% equity which puts it 4% ahead of the closest equity range.

Scenario 2:
It's folded to me on the button (shocking I know) and I raise A8o expecting to get two callers very often (>60%) and 1 caller almost every time as I'm sure that big blind is playing close to 100%.

What would you raise in that situation? Being in position, I assume that we can cut down on the equity requirements a little, but personally I'm not jumping out of my seat to raise weak Axo, small pairs, or weak suited connectors or gappers.

Scenario 3:
Unopened in early position. At a loose table, I might raise hands I don't normally like AJo, ATo, KQo b/c they figure to call with enough dominated hands that I'll still make some money when we both hit.

Scenario 1: They're calling $15 with 40% of hands?!??

Scenario 2: I think Ax is good hand on the button in a blind steal situation (same with pairs).

Scenario 3: I stay away from ATo/AJ/KQ from EP. You're going to miss most flops and be OOP the whole hand plus end up value owning yourself a lot with AT.

Scenario 1, I dont usually opennKTo from the HJ, but it’s close enough. The question is, are you going to get to the flop heads up versus the limper? If so, it’s a fine hand to iso with. If not, it’s a pretty poor hand to play, especially oop, in a big pot. Since you describe the 2 in position players as loose, I’m not sure you’re going to get heads up.

The thing you have to remember before loosening up too much is that you aren’t heads up. Trying to exploit one player, even correctly, can get you in trouble against another. I’m thinking in particular about hand 1. KTo isn’t a good hand. Just fold so you don’t have to worry about what happens behind you. Sometimes someone else’s mistake means you have to let someone else exploit them.

Situation 1: You can push hard here but I usually want something better then KTo if I am likely to get multiple callers afterwards. I will instead limp these hand and look for favorable flops. If you do play either way remember that with 4 people in the hand somebody is probably going to hit the flop. If you don't be ready to check/fold because bluffing won't work much. In these loose/sticky games you should be doing a lot of giving up the flop in multi-way situations.

Situation 2: At 100BB sure. Variance will be high because you can't tell when BB type players hit the flop but they have to miss most. Study their post flop patterns hard and learn to exploit them. There are often some weird patterns you can use on these guys.

Situation 3: if raising won't get you FE there are a couple of things to consider. Do people flat call with AK/AQ? If so then all of these hands can become traps OOP and only the better suited ones should be played. Are people generally passive? If the majority of players will check down a hand even if it beats yours then these hands play better. If people will bet marginal ones or bluff when you check then they play worse. In that case avoid the unsuited ones, only playing KQo. Probably skip AT entirely, you will be value owning yourself too often.

At this sort of table how your opponents play is more important then any theoretical aspect. Balance, range, bluffs, all of that go out the windows if you know villain only raises two pair+ on the flop. You can just concentrate on how likely your hand is to win and how much you can get paid.

Scenario 2,
A8o is definitely strong enough to open raise from the BN against 2 whales who are going to be cold-calling you w a 60% range. I'd probably just stick with my normal BN range which is fluid and can be as low as 35% and as high as ATC but is usually around 40%. The only time I'd think about reducing that range is if they were 3 betting me, which it doesn't sound like is a problem.
With A8, you have a card advantage, position and the initiative. This is like as good as it gets.
As Quadj said, 'study their post flop patterns.' if they call w 60% and play fit or fold on the flop this is a golden goose situation, and you should want to play against them as much as possible. if they are sticky and are likely to call down with any made hand then you want to out-value them. I guess that impacts your starting range a little bit, but not much. What it really impacts is how you want to play them post-flop.
One more thing, experiment with different open sizes. If you have 2 players in the blinds who want to call with practically any 2 cards, then start charging them more to see the flop. If you want them both to fold then keep increasing the raise size until you start seeing folds. If you want 1 or both to call and then check-fold on the flop, just increase your raise size a little and earn that much more.

Scenario 3,
The issue isn't how loose everyone is, it is how aggressive everyone is. If there is any 3 betting going on at all then AJ/KQ should be folds from EP, imo. You're including too many combos and making your range too difficult to defend properly. (AJo and KQo should definitely be folds to an in position 3 bettor, no?) But if the game is loose-passive and you are just likely to get callers if you open from early, then yeah, you can open with AJ/KQ from early. Being suited makes these hands much more playable. AJs and KQs are pretty decent hands in a multiway pot, even from bad position. AJo and KQo don't play as well when you are oop and seeing a lot of 5 way flops, but at least they are fairly easy and straightforward to play. ATo should just be folded from EP, even in a loose game, imo. Just wait for a better spot.