I'll tray and fill in some of the blanks but your best bet is to do research on the official sites.
1. Covered. Note As a Class A reservist you will get paid by the half (6 hours or less in a Midnight to Midnight timing) or full day (over 6 hours, Midnight to midnight). Therefore, a "normal" working evening is a half days pay (Typically 3-4 hrs), while a weekend can be up to 2.5 to 3 days pay depending on what is going on and when you report/leave army work.
2. Note that Class B has a short term and a long term sub component (13 to 180 days consecutive is considered short term so Dental only) 181 to 365 days is considered "permanent class B" nad has full dental and medical coverage for you (not your family). Class C is normally when you are on tour and you get the exact same benefits as a Regular Force soldier.
3. Note that there are two clocks in the Reserves that effect your pension. Time in service starting the day you are sworn in until you release, and time towards your pension which is calculated by time paid. The max you can do in service time is 35 years. The amount of your pension is calculated by the number of days you "accumulate" working (ie. Being paid) Class a is 1.4 days pers day of paid service. Class B is 1 for 1. So if you worked a weekend (2.5 days) you would actually accumulate 2.5 X 1.4 or 3.5 days of paid service and 3 days of "serving in uniform". So in my example, I served 37 years, but accumulated ~19 years of paid service, so my pension $ amount was based on 19 years at my 5 best consecutive years, but once I hit 35 years of service in uniform, I could no longer contribute. As for earning a pension from the PS and Reserves, I'm not 100% about that. Hopefully someone else can chime in. I do know that to port your pension over to the PS, they only count 180 days or more consecutive service as 1 for 1 time. The rest is not ported.
4. Reservists are not normally offered paid 2nd language opportunities. I have seen it happen, but usually for high ranking succession planned individuals.