yes, try

[symbol $2$1(

instead of [$2$1( message.

I don't really understand your question. Maybe share a patch or screenshot to make it clear.
Don't know much about OSC, but I guess you are routing the incoming messages, don't you? So you could just route another name/adress?
Threre are many ways to archive things, in some cases dynamic patching is the only way, but this sounds like it maybe could be done easier.

A simple abstraction of a dynamic receive, a control rate [receive] with an input to change the receive name.
Made with dynamic patching.
Not sure sth like this already has been shared.

dynr.pd
dynr-help.pd

EDIT: there is an open request on Github: https://github.com/pure-data/pure-data/issues/603 So I guess [r.mmb] does this too.

Maybe [receive $1] inside the abstraction. Or [value $1]. Or both (to get the value when abstraction is loaded and new value is sent).

[123\ 
|
[s $0-a]


[abstraction $0 a]

[r $1-$2]
|
[print]

[loadbang]
|
[v $1-$2]
|
[print]

https://www.flucoma.org/

Yes, indeed, just for display.
And polygon surprisingly is the cheapest option of the three.

For interpolation [cyclone/wave~] has more options, such as cubic, spline, Hermite and Lagrange as [tabread4~].

The [open $1, 1( are two successive messages: [open $1( and [1(, where the later is the same as [start(

Many (but not all) objects can update only at block boundaries of Pd's main blocks (fixed blocksize of 64 samples in standard Pd) .

One block of 64 samples at 44,1 kHz samplerate = 64*1second/44.1 kHz=1.451 ms

Use [vline~] instead.

[tabread] instead of [array get] !?
(Long time ago arrays where called tables in Pd.)
Read their helpfiles. You can use [array get] too, but more complicated for this.

In Pd Vanilla, right click on the blank canvas > help shows all build-in objects.

@seb-harmonik.ar 2048 points since Pd version 0.55 :
https://msp.ucsd.edu/Pd_documentation/resources/chapter5.htm#s5.1