1998 Jeep Cherokee Starting Problems

I have a 1998 Jeep Cherokee Limited, 130,000 miles on it, bought it used. It works great except for its minor problems. The one that worries me most is the starting troubles it gives me. It starts, but almost never on the first try. 99% of the time it starts on the second try and rarely, it will start on the third try. If you turn it off it will start on the 1st attempt within about an 1hr. It cranks fine and everything seems normal, but this is confusing.

Secondly, I had to replace the AC converter on it as the old one was just bad, and recharged the AC. The O-rings to where the AC converter connects are badly rotted and I did not replace them. The AC worked for about 3 days and then nothing. It just went to blowing air again. There is no residue in the engine, so I dont know where it could be leaking. How do I fix the AC? Will a leak sealant in the lines fix this?