Tonearm for Technics SP-15

my friend has a unit in a plinth with a dust-cover. it looks like OEM Technics to me, I could check. Grace arm is in a circular removable board, also looks OEM, with a long oval cutout for various lengths.

removable arm board looks like this

(seller says fits 9 or 12 sme arms

That one looks like an SME cutout. Several arms use that mounting- it allows the arm to be moved to get the right geometry.

will the Victor 7082 fit SP15?

Of course. You can use any arm because the SP-15 is designed without its own plinth, like the SP-10.

OTHER ARMS with VTA on the FLY that fit on the SP15?

Triplanar would be an obvious choice and would suit the SP-15 nicely. They originated the adjustable-on-the-fly VTA tower design used by VPI, Durand and others.

Triplanar