Anyway, fitting a modern FD would fix all potential problems with the FD causing problems with the new brifters, right?

How does it work then, the new FDs are mostly designed for 10 speed rears, so that means a narrower chain, no?
Will a 10-speed FD still work right with an 'all the rest 7-speed' system, and a 7-speed chain?

At the moment I'm actually a bit regretting about ordering the A070 brifters.. I think I should have waited a while and saved up for a complete set of Tiagra or 105.
I just hope I can get most of the old stuff working perfectly so the 7-speed system will serve me on my workout plan.

Also, I would like to investigate the possibility of fitting a smaller 'small' ring up front. The setup now is '88 Biopace 52-42. If I'm going to get a new derailleur up front,
I might as well take the opportunity to get a 'compact' small ring, one that the new FD would already support. But all the modern rings round, or is there still a similar
shape available as the Biopace? I would assume it woul feel odd if the rings had different shapes.

Continuing on the ringset issue, if I do later upgrade to, say, a modern 10-speed system, could I still use the '88 Biopace or would I need something modern to support the
rest of the drive train?