So, I have a lot of Ismaili friends where I live, and I don't think it would be too much of a stretch to say that they're a middle ground between Islam and Dharma (as least originally anyway). I asked one of my friends over why Ismaili Muslims are way more liberal than more traditional Muslims, and these are along the lines of what he said.
It seems that when some of the Gujaratis first converted to Ismailism, they practiced a syncretic Islam-Hinduism practice, and you can still see some remnants among Ismailis today (i.e. Ismailis have have their own garba/raas celebrations, although they don't have Durga in the middle of the circle, and in their wedding ceremonies, they use these wedding pots that have swastikas on them). Apparently, one part of Ismailism is the belief in a succession of Imams. Vaishnava Hindus believe in the avatars of Vishnu, and they were told that the final avatar of Vishnu, Kalki, is actually the Aga Khan (Ismaili leader), which I guess is how they got convinced to convert.
However, not just that, Ismailis also used to keep murtis of Hindu deities inside their jamatkhanas! My friend said that in his grandparents' generation, they would do sajda (Islamic prostation) and bow down to the murtis of Hindu deities like Ram, Krishna, etc. They apparently also used to believe in reincarnation. The position of Aga Khan varies among Ismailis depending on their age. The younger generation merely views the Aga Khan as a religious leader, sort of like an Ismaili pope. However, there are some in the older generation that believe the Aga Khan is either a prophet or God on earth. Eventually, the jamatkhanas decided to stop worshiping Hindu deities, and they placed a picture of whoever the Aga Khan was at the time. They got a lot of criticism from the other Muslims about how doing sajda to a picture of the Aga Khan is akin to worshiping the Aga Khan, so they eventually put that photo in the back.
Ismailis, however, tend to be really secretive about some of their religious practices. Non-Ismailis are not allowed inside the jamatkhanas in India and Pakistan, and in the US, Ismailis will try to convince other people to go and not come inside. Even recent converts are treated with suspicion, and older members worry and freak out about this. I'm guessing this is because Ismailis used to have so many unIslamic practices that treating outsiders will heavy suspicion was normal. Even today, many Ismailis face criticism about how they are not real Muslims. However many of the Hindu elements are being removed from Ismailism (i.e. Hindu deities aren't worshiped anymore, they no longer believe in reincarnation) in order to align themselves with some of the more mainstream Islamic beliefs.
Having said that, Ismailis are still a tolerant bunch. The current Aga Khan considers pluralism as an important value, so Ismailis are respectful of other beliefs. Ismailism is a more esoteric form of Islam, sort of similar to Sufism, and they believe that the God they worship is the same God that the Hindus, Christians, Jews, Sikhs, etc worship. Many Ismailis try to learn about other religions by reading the Bhagavad Gita, Bible, Torah, and such in addition to the Quran.