Suppose that, necessarily, propositions exist necessarily and that things that exist necessarily exist always. Also suppose that, necessarily, for any actual object x, there is a proposition that x=x. Then there are proxies for all non-actual objects. Say that a proposition p is a "self-identity proposition" if possibly there exists an x such that p is the proposition that x=x. Say that a self-identity proposition p is "about a" if there actually is an x such that x=a and p is the proposition that x=x. Say that the "proxies" are the self-identity propositions.
Then if w is a world (respectively, a time), P is a property, and p is a self-identity proposition, we can say that P*(p,w) iff it is true at w that: (a) there is an x such that p is about x and (b) x has P. So we have a proxy of world- (respectively, time-) relative predication for our proxies. We can similarly extend this to relations, as long as they are not inter-world (respectively, cross-time) relations.
What this seems to mean is that as long as all propositions exist necessarily, we don't specifically need haecceities to have proxies for actualists and presentists. But the gain is illusory. For if we want haecceities, we can define them using self-identity propositions: Necessarily, for all x, x's "haecceity" is the property of being such as to have the proposition that x=x be about one.
That all propositions exist necessarily follows from two plausible claims: (a) all necessary propositions exist necessarily; and (b) if a disjunctive proposition exists, so its disjunct propositions. For if p is any proposition, and q is any necessary proposition (say, that 1=1), then their disjunct is a necessary proposition, hence exists necessarily (by (a)) and hence its disjunct p exists necessarily.
I think it follows that the enemy of haecceities needs to deny, with Adams, that necessary propositions exist necessarily. And someone who wishes to deny the presentist the use of proxies needs to deny that necessary propositions exist always.