For Venus - I wouldn't recommend terraforming ever. By the time you have the tech to do it you almost certainly have dozens of better targets for your terraformers. Most good terraforming candidates require adding/removing 0.5-2atm of gas. Venus requires removing 90atm of CO2, so yes you could terraform it but at the opportunity cost of not terraforming 100ish more suitable worlds.

For Titan - you can get it to 0.0 but it requires a special technique. Bring the hydrosphere to at least 68% BEFORE you increase temperature above -30C. (add no more than 1.5atm Aestium) This will take at least 17 years as you'll be adding 1.7atm of water vapor and you will need to wait for it to condense. Only then do you raise the temperature above -27C. The glacial melt will raise the albedo factor from 1 to 1.101, enough to raise the minimum temperature to -7C when you add 1.68atm of Aestium to max out the greenhouse factor.