If you are looking for comfort, you'll have to work hard as neither Probox nor Nissan AD are meant to be family cars. Hard work can be translated as changing the seats to install more comfortable seats in Probox/AD, then you are good to go ! Toyota Fielder is a nice option but it is expensive (minimum around 12 lakhs)
You can get a mint condition Honda Civic VTi 2001-2003 (7th Gen) in your price range, and if you increase your range to around 11, you can easily get Honda Civic VTi 2004-2006 (7th Gen)(also called Eagle Eye). Civic would be the best option as its comfort is unmatched, it is reliable, and if you find a gem, it wont ask anything from you if u keep changing its oil at recommended intervals and get it properly maintained.
As for the other options, Cultus, alto or coure, none of them is comfortable or spacious. Swift is a bit better but it is too expensive for what it is and is not spacious.
My advice would be to search a properly maintained used car, such as a civic, and go for it. For the luxuries you'll get in a civic by spending 10 lakhs won't be available in any of the other options you mentioned !