1). I'm not an ORM lover in general but, yes, if you're going to use an ORM and are basing your project on PHP, Doctrine is generally accepted as the best.
3). Personal preference I guess but I hate gettext. I much prefer the pattern of using labels in your template (e.g. menu.item1) and then looking up that label in the desired language file e.g. messages.en.yml. And I've never had a problem with translators working with YAML files (i.e. the syntax is easy for them to grok)
2). I really don't understand why we should use Twig : Smarty is older, why using yet another template engine ? Or I've got a better idea : we could use the template engine used in phpBB2 : he's older !
I'm agree that standardization would be just fine(c), and I like the Twig syntax, but I think the "YATL, we should use Twig" argument is not relevant.
2). See: http://twig.sensiolabs.org/ (Why yet another template engine?)
3). Personal preference I guess but I hate gettext. I much prefer the pattern of using labels in your template (e.g. menu.item1) and then looking up that label in the desired language file e.g. messages.en.yml. And I've never had a problem with translators working with YAML files (i.e. the syntax is easy for them to grok)