Don't fall into an XY problem
An XY problem is when you focus on the *method*, instead of taking the broad view of the *solution*. X might be "How do I get 12 wires down a 1/2" conduit?" and you could spin in circles on that problem. But Y is "How do I get four 120V circuits down a 1/2" conduit?" which is easy if we knew that was the question.
So when you say "heat LAMP", that's tough as a straight problem. But if you need general heating, that changes the picture.
Use 240V appliances
There are plenty of 240V heaters out there in the industrial space, my go-to is Chromalox. You can also get 480V heaters and run them anyway; this gives 1/4 power (which is great when you need a 125W heater but they only start at 500W). 240V heat tape is also available, and some of it is the Really Good Stuff (thermoresistive heat tape that responds to getting colder by increasing power).
As for lamps, one upside of the intersection of LED and China is that lots of LED lights are made for the world market, and work on both 120V and 240V.
Lots of other stuff, including most things that take a "wall wart" power supply, look at their labeling - many will say "100-240V" because they are made for the world market - 100V Japan through 240V UK. However DO NOT wire 240V into a common NEMA 5-15 socket just so it'll plug in.
By the way, look at the pump's amp rating. If it's more than 50% of your breaker rating, all other loads should be hardwired: you're not allowed to wire any 240V receptacles because the pump is >50% of circuit load. But, (whistles and looks at ceiling) if you do wire receptacles, you want NEMA 6-15 which have 2 horizontal slots (aka they are saying "Nope", unlike the normal outlets which say "Oh No!") These are allowed on both 15A and 20A circuits (just as the common NEMA 5-15 is allowed on 15 and 20A circuits).
6-15's are available in almost any home store, you'll recognize them. Get a duplex 6-15 since it uses normal cover plates.
Also if you wanted to use a Euro socket (Australia? Supposedly Australia uses the same junction box form factors as we do) to plug in Euro cables, that is fine.
For tasks that absolutely require 120V, you can go one of several ways: For small stuff try plugging a Euro power adapter into a 240V outlet. (again never wire 240V to the common NEMA 5 outlet!) If you can git-r-dun with battery tools, ok (and again some battery chargers will take 240V via an adapter).
You could also get a portable isolation transformer.
Get serious and provision 120V out there
This would depend on luck with a Craigslist find, but I see 240-480/120-240V transformers (5 KVA) out there all the time for $100-ish. Have to be a local sale; shipping would be a nightmare. A smaller 1.5 KVA would also do, and probably be cheaper. You'd need a proper enclosure there, but you could jumper the high side for 240V (usually the other option is 480V) and connect it parallel to the pump, and then jumper the low side for straight 120V (the other option is 120/240 split but you don't need that). Pick a 120V leg and ground it; that's neutral. The other leg is hot. That goes to the common NEMA 5-15 outlets.
Don't jumper it for 120/240 and put the pump on the secondary side of it, unless you are really know what you are doing. It might be neat to have the isolation, but you don't want to overload the transformer. Actually, putting a switch on the transformer to eliminate vampire load when you're not using it, would be a nice trick.
Because this is what's called a Separately Derived Service, it would need a grounding rod (I believe). Not sure about the Code of using a 100 foot long well-pipe for a grounding rod.
And all this stuff would need proper enclosures to NEC. The transformer may come with that.