It's a big ask looking for a rod that suits everything so whatever you choose will be a compromise somewhere. I thought vundu were African and can't remember hearing of them in Asia, but if you asume they'll go to about the same size as a redtail, say 60lb as a basis (they can both go bigger) then the 50-100g rod should do it, although you aren't going to be able to horse them in.
Depends where you go for Mekong but they fight hard. If you hook a big one you might struggle with that rod. A lot of rods used in Thailand are about 6lb test.
Forget what you think you know about the fighting abilities of carp or anything else we have over here... they're p!ss weak compared to redtails and mekong. I've not fished in Africa either and haven't caught a vundu but I wouldn't expect them to fight any/much harder than redtails, which are strong for their size... they proper grunt at you as well. lol
I've not fished for tigerfish either but unless you're going after goliath tigers the 50-100g rod should be fine, unless you have to use small lures when the weight won't load the rod.
I've recently been looking for a similar rod for a (hopefully) planned trip to Mexico for roosterfish although I've not made my mind up yet. If it were me, I'd forget the carp rod and go for something like a 50-100g, 8-9ft rod. A long rod is very tiring to cast lures on. As well as the exage, another option I've been looking at is the Fox Trek Sailfish XT, which casts about 50-100g and gets good reviews.
You need to think about a reel as well... I wouldn't use anything with a graphite spool personally as they can shear off, especially with braid. One of the Penn spinning reels might suit you but I've not really looked for a suitable reel yet... maybe the quantum cabo but it's not particularly cheap and maybe not needed in freshwater.
One more thing to consider; when you fish somewhere that's very hot, the metal expands and contracts and your drag needs to be checked fairly often... at the very least once in the morning and once in the evening as the temperatures change. Mono line also deteriorates very quickly in sunny climes. I use braid but Gold Label do a mono that was designed to cope with high UV. Depends on how long your going for but you'll probably have to change mono pretty often, even the UV line.
Hooks are always an issue but Gold Label penetrators or catfish-pro bp specials are plenty strong enough. If you think you need even stronger look at the Owner gorilla hooks.. super strong.
Hope some of that helps.
Sogster, that's some feat landing a stingray on a 3.25lb tc rod mate. I used an 8lb test rod in Thailand for one about 110lb, with 100lb braid, and being on the bank it took me 2 hours of straining, sweating and swearing to land it.. I've never pulled so hard on any fish, not even remotely close! Glad I didn't have the squits at the time. lol. Tbh, it nearly broke my back and I don't really want to catch another one! lol. Another fish ticked off the bucket list though.
