The reason I have so much def and magic resist early game is so you can actually tank. If you just have tons of hp early game you'll still get rocked and wont even really be a tank. If you are to build early defense it benefits your team dramatically in early to mid game team fights in event. About the HP Quintessence's, They would help but its the matter of having as much as AP as early as possible so you can harass. If you were to go with HP Q's you would only get about 5 AP in total with an extra 90 HP if you go with AP you get 45HP with 15AP. I have been forgetting to print screen my games but I just played this exact build 3 times in a row going 20-2-10+ each game. It works very well if you know how to use the build. Zhonya's Hour glass is completely plausible but, this is not a hybrid build and you want them to get on you NOT YOUR TEAM as much as possible. This would only cause them to attack your team. This item would be more self beneficial not team beneficial.

Honestly, the build order here makes no sense. The reason tank vlad can be effective (like you mentioned) is because he can put out pretty good damage because of the health he has (which transforms to AP). Therefore I don't understand why there is so much armor in your beginning items.

Here is what I would recommend for a tank vlad build:
Spirit Visage-Merc Treads-Warmogs-Zhonya's Hourglass-Abyssal Scepter, With Items after that depending on whether they are more magic or physical damage. If they're magic, grab a FoN, if physical, randiun's works.

Only other option is to just build heart of gold before abyssal and then waiting to finish raniun's until later.

Warmogs that late in the game will not be worth it and why AP quints and not flat health if you are building tank? I think they would benefit you more.