Well, looking into everything, it seems to me that:
1. A Feat would be unnecessary unless the Ranger wanted his Animal Companion to be a little better.
2. To offset the lack of an Int score, the Soulfused template can be used.
3. The Construct would more likely be treated as a higher level Companion.
4. If anything other than the Effigy Template is used, it requires looking into Pathfinder or otherwise making homebrewed adjustments onto other Construct creatures.
Thanks to everyone who contributed, as this has really helped a lot. In all honesty, I'd been working on this for a little over a month now trying to squeeze any improvement out of what was there. I'd only been able to make it as far as the Effigy Template, which having no Feats or Skills makes it utterly useless as a Companion.
Now, I think I know what we will be using and I'll clear it with the DM and let the Ranger know he can have what he's always wanted, a mechanized companion that understands him and his machine man ways, not just a mindless automaton that follows orders without question.