I've heard of people with their PPL (and higher) going through IFS. I mean you're not really defrauding anyone if they never technically ask you.. but if they say 'do you have your ppl?' and you blatantly lie, that could end up causing some trouble.
In response to above: Well i'm not in the program or anything, but apparently they ask you so I would not recommend lying. It's not worth risking the loss of your flight career for 25 hours. If you feel rusty, go get a few hours at some part 161 school.
1. I have never heard this (nor did I see it when I went through). Unless they lied and weren't caught, I doubt it.
2. They do ask you. Blatantly. You actually fill out a form identifying your flight experience. Go ahead and lie... see what happens. If I can go and check out what ratings you have, Big Navy can do a lot more.
3. It's part 141/142/61. There's no such thing as a part 161 school. You're thinking of Part 61.
4. Unless you have direct experience with the subject matter, I'd let someone more experienced answer.
Bottom line: The extra time in the cessna won't help you in the T-34, so the only possible effect is that it creates another step which could possibly attrite you. (unlikely, I know, but it is the only net effect).