Good advice from Ian Faisal (#3). Twenty or even thirty years ago when I was hanging around Java and shooting al ot of film, there were small (mostly Chinese owned) studios everywhere offering surprisingly good quality B&W D&P services everywhere. Now they are all gone, but the equipment they had - and I saw an amazing variety of it - may still be around. All the big photo studios in Java were doing virtually no business by the 1990s and had closed by 2000. I know of one in Surabaya, where I still visit, which had been in business since 1900 but finally shut its doors in 1998. Everything in it (I recall a 8x10 Linhof portrait camera with roll film backs on a magnificent wood and brass tripod) had been presold and it was all packed up and sent to Japan a week later.
Finding it will be an adventure. Advertising for it may not help much. You will have to travel around and ask at local photo shops.
As in all used equipment the quality will vary, and you won't be getting it dirt cheap, tho. Indonesian Chinese are aware of the value of what they have and will charge you accordingly, as they should. Buying that equipment in the 1960s, 1970s and 1980s was very expensive for them with every sort of duty and tax added on to the equipment when it was shipped from overseas. I recall a well-used Rolleiflex TLR in a shop in Malang, the asking price (or at least the starting price) was enough to buy a new Hasselblad 500CM at the time. So I passed. The Rollei was still in on the same shelf in the shop two decades later when I last visited. It may still be there, covered in dust and riddled with fungus. The same shop had a stock of refrigerated 120 Fuji color negative film which I bought for A$2 a roll, as the owner was getting out of film and wanted to move it.
There is, or was, an Ebay-like web site called Tokobagus. It may or may not still be around Such things come and go quickly in countries like Indonesia.
An Australian enlarger will work with Indonesian current. Getting it safely to Indonesia, however, will be an exercise in logistical nightmares. Shipping by a professional firm would be the best way, but be prepared to pay at least a kidney for the service. the post office won't touch it - there is an old joke in Surabaya that anything sent via the post office should be big enough so someone on the staff won't steal it, but a parcel containing a 4x5 enlarger won't fit on a motorcycle, so it's unlikely anyone will make off with it.
As for shooting and processing 8x10, well - I hope your pockets are very deep and your wallet very big! You'll have to import your film and chemicals, so think MegaBucks. 4x5 would be more affordable, but again you will likely find yourself stocking up on film and dry chemicals whenever you visit other countries like Singapore or Japan Not sure it will really be worth your time and effort. A more, shall we say practical? approach would be to rejig your thinking and planning and go MF, with care and attention and applying a sensible workflow to your shooting you will get results 90% as good as with LF, with 90% less effort and inconvenience.
AgX (#5), there are no abandoned government darkrooms in Indonesia. Nothing is ever abandoned in Indonesia The gear would have been sold off a long time ago.