There's nothing wrong with a braze-on FD plus adapter clamp. It's the most versatile setup.
It also gives the most stable arrangement that mis-shifts least, if correctly set up.
It's not clear to me why you think you need a new FD at all. Especially if you are keeping 10-speed shifters.
No new FD required provided the OPs FD has enough capacity. Even then, depending on the rear cassette and frame geo, the full capacity of the FD may not be needed.
Just changing the crankset is not in itself a reason to change.
Campy FD's have been universal (compact and regular) for quite a long time now - 7 years or more? Just buy Veloce if you need a new one. There's absolutely nothing wrong with them.
The "universal" type FD came in in model year 2007 ... the CT type prior to that works well with the correct lever ... the current 10s FD will work "OK" with the OPs levers but works better with a 2009-2014 UltraShift lever.
More information about the year of the components you are proposing to use is really needed.
Yes and no - the basic problem is that mixing a 10s chain and an 11s crankset, especially a Compact, is a bad idea.
The chainrings are effectively closer together, so you hit two problems - first the predictability of downshift from big to small ring is less - it's easy for the chain to overshoot and trickier for the FD to control this (although a dog-fang or similar *can* be employed) ... second, and the shorter the wheelbase, the bigger the problem, the wider 10s chain tends to fould the back of the big ring when cross-chained - and whilst we all "know" we shouldn't run big ring to biggest two sprockets and small ring to smallest two - most of us will grab those geras at need. If the chain catches the back of the big ring in some circumstances, an an effect like chainsuck ensues. At least, this will damage the surface finish of the stay. At worst, it can damage the stay, the chain and the inner chainring - so it's to be avoided.
There is a FD mis-match - the 10s derailleur struggles to control the chain well given the narrower inter-ring gap and front shifting is compromised. Changing the FD for an 11s item as a workaround is alo not a great plan as the gate is too narrow for the 10s chain and there is a lot of faffing required to get an FD position and cable tension that will allow clean chain passage - and trimming will almost certainly be required when using the biggest two (maybe 3 depending on cassette sizes and frame geo) at the rear on the big ring, and the smallest two (or matbe 3) on the small ring.
Personally, I'd avoid it and either look for a NoS UT 10s chainset in compact (there are some out there, still), or mount 10s rings on an older 11s crankset, as the ring spacing is actually managed on the rings, not the crank spider tabs.
ps. Ultra-torque is not "old school" by most standards.