Marinated tofu is essentially a myth perpetrated by well-meaning people who are, in my experience, culturally pretty far removed from cuisines where tofu is heavily used. Tofu is not especially porous, because it's texturally very similar to a custard. Maybe osmotic pressure will result in a little flavor transfer to a custard, but it's not the most efficient way to do it. Marinades are pretty rarely used for tofu in Asia in my experience.
You're more likely to see pan sauces or dipping sauces, or occasionally a topping added after cooking. But people in Japan, China, and Korea will generally expect a much fresher, beanier tasting tofu than you're likely to find in a US supermarket, so there's not as much of an impulse to cover up the flavor. In the US, thanks to generous expiration dates and a fairly unpicky customer base, a lot of tofu sold in supermarkets is slightly soured and just doesn't taste very good.
The primary effect of the dry frying technique on the page that you linked to will be to create a bunch of nooks and crannies and irregularities at the surface of the tofu that will make more of the sauce stick to the surface of the tofu, and the reduced water content will make it less likely for the tofu to break apart. The higher surface area may contribute to the perception of more flavor because you'll have more of whatever salty solution you've seasoned it with on your tongue. But inside the tofu you won't really get much additional flavor.
Freeze-dried tofu removes most of the water from tofu and small holes form where water had previously been. When rehydrated and squeezed, you'll be able to get a lot of a marinade to enter the tofu because there's plenty of ways to get in there. The side effect is that the texture will be completely transformed into a sort of spongy mass, which can be pleasant on occasion but eventually gets a little tedious, so freeze-dried tofu is eaten only rarely and in small quantities in Japan and most of China. It's frequently seen in lamb hot pots in China and occasionally in rustic simmered dishes in Japan. You can come close to the texture by actually freezing your tofu and then pouring boiling water over it a few times, but I usually just buy it from my local Japanese market.
One form of marinated tofu sometimes seen in China involves very aggressively pressed/weighted tofu that's been pushed between a muslin-like cloth for an extended period to drain. It's often soaked or cooked in a soy and sugar solution with various spices, but most of the flavor and color is concentrated near the surface; only some of the salt really seems to get to the center of that, so it's often made in fairly thin blocks.
I've seen patted and pan-fried tofu used in Korea and occasionally in Japan, but it was typically not marinated; it was typically cooked in a little oil until lightly browned and served with a dipping sauce of freshly-grated ginger and soy sauce.
Deep-fried tofu also creates more surface area for sauces, especially if dusted with a starch like katakuriko or cornstarch, but it's also generally only an occasional indulgence in Japan, China, and Korea, and also mostly affects capturing flavor that touches the surface of the tofu. (I'm less knowledgable about food as served in Southeast Asia, including Vietnam and Thailand, so I can't speak as authoritatively for all countries with a long history of serving tofu).
I don't know if it works well, but a Japanese TV show suggested that you can soak tofu in salted water to reduce the tendency for soft tofu to fall apart when stir-frying or braising. I haven't seen enough of a difference to justify regularly applying this technique and I haven't done a side-by-side comparison to be sure that it actually has much of an impact. But based on the guidance from that show, I suspect that if the marinade has any effect on structural integrity of the tofu, it's due to salt and osmotic pressure.
Best Answer
Higher temperatures, as a rule, mean less absorption of oil because the force of the steam trying to escape from the food pushes against the oil. Here is a link to a scholarly article discussing the mechanics of fat absorption in the production of french fries (complete with a table of results and diagrams). Interestingly, the author says that potatoes deep fried at more than ten degrees Celsius below the recommended temperature of 180-185C leads to 40% higher fat uptake. I expect pan-frying leads to a much lower total uptake of fat, but I am sure the principle is the same.
(For a fun explanation of the mechanics, here's Alton Brown in part II of the "Man Food" episode of Good Eats. Enjoy.)
Now, your question was aimed at tofu (or some spongy equivalent), and you asked about the effects of flour vs no flour. I could not find any articles with data on those exact elements of your question, but I suspect the answers will all derive from the same underlying principles. In other words, as a rule, cooking at low or medium heat means that the spongy and/or dredged product will tend to absorb more fat than at high heat.
So, then, why do the recipes you have seen typically call for cooking tofu on "medium" heat? My guess is that the recipe authors found that high heat makes the outside brown too much by the time the inside is "done" to the authors' preferences -- and perhaps a little extra oil in the tofu makes it taste better. I am not sure, however, because most of the recipes I've seen call for searing a crust onto the tofu using medium-high heat.