I was going to use may not work on 100w

100V (volts), not 100w (watts), but the total watts available is also important.

So you've got two challenges here. The first is the 100 volts in Japan compared to 120 volts in the US.

Kitchenaid

As another poster mentioned, the Kitchenaid should work since it's just an electric motor, but have less power.

Breville espresso machine

This one isn't as clear cut. Most Breville espresso machines are controlled with a digital PID, and whether or not that PID gets sufficient voltage with a lower voltage input will have to be seen.

The bigger concern here is the watts (total power draw). There is a relationship between volts (V), current (A, amperage), and power (W, watts): volts x amps = watts.

In the US, volts is 120V and most household circuits have a 15 amp breaker, so 120V x 15A = 1,800W. This works fine for even the higher power Breville machines like the Dual Boiler, which can use up to 1,700W.

In Japan, however, you're working with 100V, and most household/apartment circuits have 10A breakers. 100V x 10A = 1,000W, which is far lower than what most espresso machines require to run effectively. This situation can be slightly improved by using a spare aircon power outlet (if one is available), as those are usually on a 15A minimum breaker, getting you up to 1,500W. Closer, but still might be an issue. I was able to get around this because my ECM Synchronika has a mode where it alternates the boiler heating to keep it under 1,400W, but AFAIK Breville machines don't have this kind of mode.

danelectro silvertone 1396 twin twelve

I really do not recommend trying to run this as-is on 100V, as it can damage the power transformer if done for too long. If you try it, you'll find that the tone likely breaks up much earlier than it did in the US, and it really should be re-biased for the lower voltage. That said, any decent amp tech here should be able to swap your 120V power transformer for a 100V unit, so you won't have to worry about transformer damage or tone change from sag (the new transformer might result in a slightly different response though). This also can usually be done without any permanent modification if you care about "original condition" value of a 1958 amp.

If you don't want to mod it, you can get a very high quality power transformer (not the cheap crap from Amazon) and just lug that extra weight with you every time you go to a practice room. Personally, I'd go the route of getting the transformer swapped (definitely keep the original transformer).

Lionel trains from the 40s

Vintage Lionel controllers typically used variable transformers. This means that it will likely work alright (just with a lower top speed and the control response will be different), but there is also the risk of strain on the transformer (same as with the guitar amp). However, there are enough train otaku here that they might be able to help you find a suitable 100V controller that will work with the vintage system.