The shifters are definitely newer than the frame. That style with the rounded tops was introduced for the 1998 model year. Crank and derailleurs could be 1995 and were used through 2008. 1995 was the first year that Campagnolo put the model names on the components but they were small and...
Spacing on 8, 9, 10 speed cassettes are different between Shimano and Campagnolo, so I wouldn't expect shifting to be perfect.
What model Shimano shifters and what era 105 derailleur did you try?
The ST700 has the same rack mounts as the other touring models. For more braking power you could add a drum brake. Sturmey Archer even makes one that also has a dynamo...
That T2000 looks like a great deal.
I have a 1988 ST700 I could sell. It has caliper brakes and a cheaper build than the ST1000. I believe it's a 23" frame.