Hi @arwqiime,
Since the representative OTU sequences produced by closed-ref OTU clustering are the closest reference sequences (with the SILVA ref seq ID), I believe you can actually use one of the pre-aligned trees that come in the SILVA release. These will be based on full 16S alignment and other curation may be applied... but in any case it would save you time. You will need to filter the tree to only contain observed sequences, of course, if you are planning to view this tree.
That is not possible in QIIME 2 — but follow this thread to see a duplicate question and solution.
I hope that helps!