We had no problems finding a ride to Ollanta, however as you have a really tight schedule, arraging a car in advance is a good idea. And I'm not even sure your route is doable in 3 hours.

Specific responses to your questions.

1) 3 hours tight but doable. Assuming everything from no flight delays, traffic around the airport and who knows what else.

2) Limited spanish is one of the issues. Another one might be if you get a cheaper local ride, make sure the driver doesn't try to pull in other passengers or pick up his sister-in-law and cousin at the same time. That can add lots of time. If left to me with such a tight schedule, I would just eat it and be sure that there are no hitches.

Have fun!
SF

With on-time flight performance, made the connection with lots of time to spare. Flight from LIM came in 5 minutes late and had to wait 15+ minutes for bags. Driver was there so a quick exit out of CUZ. On the way out of town well before 1pm. Was in Ollantaytambo by 230p so had enough time to stop by the hotel to drop our bags before going to the train station to buy tickets (which can take a long time) getting there by 245p (for a 335p train). Perurail tickets are non-refundable so we didn't want to buy in advance.

FWIW, the Perurail Expedition trains have fairly-ample luggage racks as well as baggage stowage space between seats.

PeruRail having "ample luggage racks" puts them at odds with Inca Rail! Very tight and they were monitoring what people were bringing on. Didn't see them tell anybody they couldn't board, but if somebody had brought a rollaboard along with other stuff, might have been an issue. There's room in each car for maybe 3 or 4 rollaboards at one end, and the space between the seats won't fit anything larger than a handbag or laptop case.

Did you climb the big mountain (Wayna Picchu)? That was quite a monster! Not so easy for someone not used to hiking. And the trail to the Inca Bridge, which people on TripAdvisor said was easy, level, etc. Maybe if you hadn't done Wayna Picchu first.

We spent only 90 minutes in Cusco before the flight out; I had no interest in Cusco before the trip, but now think it would have been a nice place to spend a day. Maybe at the end, to make sure the altitude didn't get to you. Which, thankfully, never gave us any issues at all, other than being a bit out of breath when you'd normally be fine.

I would consider the Inca Bridge trail to be relatively-level. Some steps in the beginning but nothing too hard. Nothing compared to Huanapicchu (which I also did). It's the steepness at elevation that made that one difficult. I'd spent the previous 4 weeks at or close to sea level (22 day cruise from Vancouver to Chile) so had no altitude conditioning at all (not that I have any where in my range).

Nothing to do for altitude other than living there for at least 2 weeks.

I also did the walk out to the Gate of the Sun and while that was level, it was also quite rough.

FWIW, I'd recommend heavyweight boots or those who sturdy soles as you'll feel every single, uneven rock that the Incans paved with light-weight hikers.

Darn, knew I should have used Strava the whole day, then I could prove the Inca Bridge trail isn't level!

If unfamiliar with Strava, follow this link to see what people have mapped around Machu Picchu.