Is it okay to run two amplifiers for two speakers

To bridge each amp I should connect the positive speaker terminals only?

Don’t confuse bridging with biamping. Biamping is using the two channels on a stereo amp to run one speaker by connecting one channel to the bass and the other to the treble/midrange if the speaker is set up to do that. It has minimal effect other than to take some load off of the amp.

Bridging is using a stereo amplifier as a monoblock by using both channels to drive a single speaker (not biamped). But this is dangerous unless you know the amp is made to be bridged and you know how to set it up to do that.

ALSO, with bridging, you need to look at the speaker specs. You should not bridge into a 4 ohm speaker because the load on the amp is effectively 2 ohms which will blow many amps. If the amp is stable to a 2 ohm load then it may be OK.

I have a PA-7...it is a pretty powerful amp. I don’t think you need to use both unless your speakers are huge power hogs. Suggest you not bridge but you can consider biamping just to keep the gear in use, but it won’t have a major impact. Active biamping is different, but takes technical work - not recommended for the your average music fan.

I am going to stick to my PA-7aii only. Thanks.

Yes as long as they are the same amps 

You run them as mono blocks.

If you have two of those amps, you could run them as monoblocks by running one channel of each amp per side. The benefit is zero crosstalk from the physical separation, and there's an advantage in each side having it's own power supply.  It won't increase power, but there are advantages that might result in audible improvements by way of refinement.