new r-410a ac unit installation procedure(w/old unit r-22)?

excalibur1

recently had my house 4ton ac unit changed out and now have several questions...
Old unit was R-22, new unit is R-410A, contractor did not change old refridgerant lines, assuming they were flushed should they have installed a filter and or dryer? I do not see either outside, could they be inside the new unit or are they not required when both inside and outside units are replaced?
Next question about not changing the ac lines-according to info read on these message boards they may be undersized... I looked at the specs-7/8's and 3/8/s, measured the existing lines and i think they are 3/4 and 1/4, is this much of a concern?
if so what could result if left in current state?
also the a/c wouldn't come on 1 day ago, and i found a 30amp breaker mounted in the air handler(in the attic)had tripped, i reset it and it is working fine(last 24 hrs), but what could have caused it to trip?
And last of all after i reset the breaker and unit running, I notice cool air(in hot attic) so after investigating, noted air coming from around condensate drain line and another place.
Can i seal these up with caulk or foam? also found laying on top of air handler what looks to be a rubber plug to go around the drain line if it were cut and fitted...?
If it matters new units are tranes, outside is xr13, inside air handler is 4teh,(all electric)