According to drawings in the Suzuki Parts Catalog, the interface between block and bellhousing on the '89-'98 1.6 liter is different to that of the '99 on, i.e. the blocks are different. So an adapter for a 89-98 will not fit a bellhousing for a '99 on.
...the question is whether or not it can be done, with the same ACME adapters in a 99 with a different engine & transmission - and I believe it can.
Bearing in mind that the 99 bellhousing to engine face is different to the 89-98, why do you believe that?
Based on your previous post you're looking at the drawings in the part catalog - when you posted it, I looked at those drawings and noted the difference - however - I see no reason why Suzuki should have changed the G16B blocks and it is my belief that the bolt patterns are unchanged.
There is a plate that fits between the block & the bellhousing - exactly where the ACME adapter would go - it's the same part number (11311-60A01) for both the 89~98 & 99+ vehicles - if this plate is the same for both generations then the bolt patterns
on the block will be similar if not identical.
The shape of the bellhousing front face is not that critical - the newer bellhousing has more "web" in between the bolt holes. but as long as those bolt holes line up, as I believe they will, then you're good to go.
Also - I don't know if you're aware of this - the 2.0 motor has been swapped into the first gen Trackers, where apparently the biggest issue is the need to modify the 1.6 flywheel to fit the 2.0, since the 2.0 flywheel will not fit in the 1.6 bell housing - according to the Aftermarket 4x4 writeup - those engines also share the same bolt pattern.
If you can bolt a 2.0 upto a first gen bellhousing, and you can bolt a 1.9tdi with an adaptor, upto a first gen bell housing - in theory at least - you can also bolt the 1.9 TDI with adaptor upto the 2.0 bellhousing.