I dont have that seat post ... plain 7/8 top type offers the option of mounting the saddle clip ahead of the seatpost.. Or to the rear ..

you may seek out someone with aluminum welding experience to modify or fabricate a replacement .

Bike Friday is advantaged by having several frame sizes , most/all others just one .. yours seems that.

yes butterfly bar, horizontal, will be a shorter reach.. as shown vertical just up/down