Before reading this, please excuse my lack of knowledge in mechanic lingo! I will try my best to explain the problem in noobie terms

I have been trying to fix the many CEL codes for a few months now. I have been conducting a guess-and-check systematic way of figuring out the problem (starting with the cheapest and easiest fix) and cannot seem to fix my car. I went to the Audi dealership for my first set of CEL codes, before replacing my ECT sensor and alternator, which were as follows:
P1606 Rough road spec engine torque ABS-ECU electrical error in circuit- static
P1296 Malfunction in cooling system- static
P1176 O2 Correction behing cat, Bank 1 control limit reached- static

The current codes from Advanced Auto are:
P0118 ECT sensor circuit high voltage
P1128 Long term fuel trim mult., Bank 1 too lean
P0441 Evaporative emission system incorrect purge flow

I understand DTC is a general term since this reading is from the local auto parts store.

Now for the list of fixes I have already performed (in chronological order):
Check all coils- good
Check all fuel injectors- okay
New spark plugs
New MAF sensor
New air filter
New thermostat
New alternator
New ECT sensor (the connector/plug in one of the four prong holes looks a bit corroded)
Coolant is full
I have been told that I need to replace my fuel pump, but I have been reluctant to do so since my car does not sputter at high speeds, lose power while accelerating, surge with power or have problems on maintaining speed on steep inclines. The ONLY symptom is trouble starting. This is occasional. When it has trouble starting, I will have to turn my key to let the engine turn over at least 8-12xs before it sputters to a start. It has trouble idling (sometimes I have to give it a bit of gas, which occasionally helps) for the first minute, then it will rev to 3000RPMs, then fall back to 900-1000RPMs. This problem went away once I changed my alternator and ECT sensor...until I filled my gas tank the first time after the fix The starting problem came back. The next fill up, it started fine. Oh, and now my radio panel loses complete power randomly This started after I changed my alternator and ECT sensor (I unplugged my battery to do this). I swear my car is bipolar. I am at a loss for what to do next. Please, any advice would be greatly appreciated!!

My car is at 185,000 miles and is a manual. I try to do all the work myself so I get to know my car all personal-like And to save money haha