agree with 2 and 3 entirely
Yeah we have swopped out a throttle control from an old Johnsohn to a new Tohatsu (these really are very nice Throttles) providing your cable ends and the new controls are the same is very easy.
aftermarket controls can be bought from teleflex and some other manufacturers but they often don't feature a trim switch. The Standard control cabling is I believe 33c (could be wrong and I suspect we'll soon find out
) but that may not be what is used by the Suzuki or Tohatsu.
Your suzuli and Tohatsu dealer could confirm that, you could also consider a new suzuki control cos I don't think outboard controls normally come without an interlock,
Did you say that the control is central mounted and if it is what make is it.