Yes. See Nevada’s post above. Servicing the sensor means resealing the nut that holds the sensor to the wheel and installing a new valve, or replacing the valve stem on the style of sensor that uses a rubber stem.
Back in the old days of simple rubber valve stems, we replaced the stem, because “The tire’s not new unless the valve is too!”
1st thing, we don’t know what vehicle you are even talking about, so hard to give you an answer on the tires…
That being said, a generic answer for a standard FWD or RWD only vehicle is, you can install 4 different make and model of tires and it will not hurt the vehicle, now if the vehicle has ABS, then all 4 need to be the same size or same circumference (very close anyway), BUT, it is always better for all 4 to match in everyway, if only able to replace 2 at a time, then replace the 2 worst tires and put them on the rear, if only able to replace 1 at a time, then it is what it is, but new to rear, just be aware that if the tires do not all match, that it can and will affect the stability, braking and cornering of the vehicle…
Also make sure you have the correct speed rating for the vehicle, I have seen some of the Accords and Camrys as an example, that call for a V speed rated tire and shops install H rated (or customer refused to pay the few $ more for the V’s), and although technically OK, they will vibrate due to the sidewall flexing more.. And it is best to never drop more than 1 speed rating on a vehicle either as that can/will affect the stability, cornering and braking of the vehicle also… Meaning if the vehicle calls for a V rated tire, don’t put a s or t rated tire on it… OK to go up, just not down 2 or more…
It depends how you are using the car. For 10 years I lived less than 3 miles from work and had a “work” car that carried just me and my radio box,anternnas and overnight bag. Fastest speed limit on the way was 40 mph. The only thing I cared about the tires is that they were legal.
Hence the reason for a generic answer, there is always someone on the forum that has a reason to…
I can take you down plenty of roads around here with 30-40 mph speed limits where you either slow wayyy down or have the correct tires for the vehicle in order to make the curve… Lots of curvy - twisty roads around my area, not to mention mountain roads with curves where you can check your own brake lights going around, they are so sharp… lol (if you don’t get that, you have never driven on roads like that a lot).. Or you are flat out backing everybody else up behind you…
Straight 4 lane level rd.
There was a time in my life, for about 5 years, when I was in the same position.
I worked in a gas station and my car always had the “best” of the worn out tires that our customers had when they came in for new tires.
I often drove with 2, 3, or 4 different sizes on my car.
It’s a reality I faced back then, and many people still face today.
What are those??? 
In that case, you really couldn’t afford to own a car.
With over 3 million miles of driving in 42 of the 50 states there is no kind of road I am a stranger to. In Sequoia/Kings Canyon Park there is a road to Crystal Cave. We were driving a full size Ford V8 rental. The sign at the entrance said it was a 45 minute drive.
The problem was, it was only 20 minutes before the last tour. We made the tour. The rental car was not the same after that.