One person doing a full length animated film isn't a very realistic goal, but it's possible if you're dedicated enough. You'd be better off building a team of artists whose work you are familiar with, but that could run into some pretty hefty cash unless you approach people who are looking for exposure for their work. There are forums online where you can ask for contributors that will do work for credit, but you can't always be too picky with them unless you're willing to pay.

M4 and V4 can be animated with style if the right talent is handling it. There are some pretty decent animations out there on youtube and other sites that demonstrate it, but none much longer than about 10 to 20 minutes or so, and even at that it takes many months and a lot of dedication to pull off a quality animation without the help of mocap and a more complicated rig than what the average Poser figure (M4/V4, etc) provides. These rigs can be built in Poser, but they're easier to build in Maya or another more appropriate, professional app. A game engine wouldn't be a wise choice, as RorrKonn pointed out, unless you really know the game engine you're using. You could use the engine for cityscapes and such, and Poser for animating the characters with their stock rigs (or a custom rig if you're willing to take on and learn that challenge) then composite it all together.

The online render farms may be a no-go for using DAZ models tho. That's the point I was trying to make earlier. You will need to read their EULA and find out, or ask them directly for clarification. And unless you're having all your content custom built (clothing, scenery, etc), you'll need to check the EULAs of each of those items as well, or check with the individual vendors who own them, to see what their EULAs say about online rendering with their content. Some are fine with it, others won't allow it. If you build your own farm then you won't have to worry about that. It's the uploading of content to a render farm that many content artists disagree with. You can buy relatively inexpensive servers off e-bay and other sites to build your own farm and network them all together. One member here who could give you some pointers on that is SeachNasaigh. 

And in regards to having custom face sculpts done, you will likely need to get a model release from each of the people you're wanting to have likenesses made of. Many artists won't touch it without such a model release. This comes up pretty often here, where people want a custom morph of someone - usually a female for V4 - and the same thing is stated. You and the artist both are risking legal trouble if you use someone's likeness without their permission. Just because there are some celebrity likenesses in the various marketplaces and freepositories doesn't make it legal. 

Not trying to discourage you, just giving you a heads-up as to things you need to consider.