At Kirkcaldy the only 'Intercity' evening peak will be the 1740 Edinburgh-Inverness which is already a 3 car 170.
The rest of the peaks are Perth (1633, 4 car 158), Dundee (1700, unsure) and the all stops Fife Circle's. The Fife Circle services will always be unit's, I imagine the majority, if not all of the Edinurgh-Dundee's will also be units, the Edinburgh-Ladybank-Perth's probably a mix of HST and units.
Edinburgh/Glasgow-Stirling-Dunblane will remain as units as they are not classed as 'Intercity' services.
There is a 1628 EDB-ABD, 1641 GLQ-ABD, 1737 EDB-ABD & 1741 EDB-INV (this one only misses Inverkeithing) which if 6 car could stop at Stirling, Inverkeithing and Kirkcaldy and reduce pressure on the stopping services if longer HSTs were available. The stopping services will I presume still be units (electric around Stirling) with the Fife loco hauls being discontinued when enough 170s are freed up.