File as resident alien using first-year choice?

I'm in the US on F-1 since September 2014. My spouse entered US in March 2017 on F-2. On October 1st 2017, I changed from F-1 to H-1B and my spouse changed from F-2 to H4. My spouse had no income in 2017 (US or India)

I do not meet the green card test or substantial presence test for 2017. Hence if I were to file 1040NR, I see the following disadvantages:

- cannot file jointly
- cannot claim spouse as exemption (since India-US tax treaty is only for students and I was on H-1B at the end of 2017)
- cannot file for her ITIN (W-7) since no valid reason to file (claiming exemption is a valid reason, but I cannot claim as said above)
- cannot use TurboTax (doesn't support 1040NR) or Sprintax (doesn't support HSA forms)

But I recently read about First-Year Choice (Pub. 519) and I think both of us may qualify to elect as dual-status aliens, and elect to be treated as resident-aliens for entire year of 2017. This is how:

- We were present for at least 31 days in a row in 2017 (October 1st 2017 till Dec 31st 2017)
- We were present for more than 75% of the remaining period (Oct 1 - Dec 31 2017)
- And we may qualify for Substantial Presence Test in 2018 (may not be by April deadline)

If so then I can use TurboTax for 1040, and also file married jointly and claim exemption for my spouse. Is that correct?

Also I'm not sure when we qualify for Substantial presence test in 2018. Do we need to file Form 4868 for an extension, jointly? And my wife doesn't have SSN/ITIN so what should we mention on the Form 4868? We plan to add the form W-7 (ITIN application) to our joint returns that we will file later (when we meet substantial presence for 2018).