Can I drop the friend off there, to cross the border on foot, without me dealing with the border control guards of either country?
I did this today albeit my "friend" was called RideWTA which offers a flexible ride service on the Route 75 and that drops you off really close to the border. I can't recall whether it was 2 and B or C but it doesn't matter much. let's look at the map, you will start in the lower right corner:
walk up 2nd street, cross the parking lot, you can see the green trail you need to take. Let's take a look at the satellite imagery:
you can see it's a paved winding path which takes you to restrooms and a marked crossing on Highway 5. Cross to the other side, there's a sidewalk, just walk on it, you can't make a mistake because it only goes one way from here. Ignore the "park is closed" signs, we are not going into the park anyways. You will reach the border soon, wait a little, the border guard in the booth handling cars will call you fairly soon. I didn't have ArriveCAN working but it wasn't needed, I showed him a vaccination record printout and that was it.
I walked a few minutes further up to Beach Road, there's a bench you can sit on and a little bay a car can pull into https://goo.gl/maps/VuoJ2s83hMujZS6w7 to wait for your Uber. If a friend picks you up: while Google Maps doesn't show it, there's a sign here saying last chance to turn around before entering the USA so this is a good spot to wait for them if they are coming from North/West. If they are arriving from the East, they can follow 0 Ave which becomes Peace Park Drive after a turn and that becomes an unnamed long onramp to the 99 completely fenced off from the border crossing. Impossible to make a mistake, there's nowhere else to go.
Back to Uber, what is our destination? There's a bus stop at NB King George Blvd @ 8th Ave just off the highway, it is just 1.5km away if you really want to save money and then two buses will take you to Surrey Central on the Skytrain. But I would strongly recommend taking that Uber as far as White Rock Centre bus station Bay 5 (5.4km). This was a <13 CAD ride for me. You could plug in 1640 152 St as a destination, it's a store with a small parking lot right at the 351 bus stop. This bus will take you straight to the Bridgeport station on the Canada Line -- much more convenient than two buses to Surrey, at least for me. (There are buses from the NB King George Blvd @ 8th Ave to White Rock Centre as well.)