Electrical – Replacing 2 split receptacles with 2 GFCIs

First off, the first electrician is wrong in saying that the use of a crimp-type terminal in house wiring is categorically unsafe. Crimp-type terminals listed under UL 486A for use on solid wire of the given gauge are considered acceptable for use in building wiring, as per UL 486A section 1.1:

These requirements cover pressure wire connectors and soldering lugs for use with copper conductors according to the National Electrical Code, NFPA 70.

and NEC 110.14(A):

Terminals. Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors.

Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.

However, I would be quite hesitant to call this specific application fully Code-conformant -- garden-variety listed crimp terminals are listed for use with copper wire only, and it would be unlikely that the previous homeowner had access to terminals identified for use with aluminum wiring.

EDIT based on updated info about the devices:

Since the existing devices are copper only, your options go as follows (in order of preference):

1. Find an electrician in your area who is qualified on the Tyco/AMP COPALUM system for pigtailing copper to aluminum -- these have a long, successful field service history, but require a specially qualified electrician to install, and are rather expensive -- you might be able to get the seller to shell out for this, though...
2. Use the AlumiConn connectors with a torque screwdriver for pigtailing. This is something that most electricians can do, or you can DIY if you know your way around electricity and have a torque screwdriver -- the AlumiConn must be torqued to spec to meet its UL listing.
3. Replace all the devices with modern CO/ALR types. This is a last resort as CO/ALR device performance has been historically variable, unfortunately.

TLDR: Being energized isn't what kills outdoor GFCIs. The weather is. Put 'em indoors and protect the (plain) outdoor outlets using their LOAD feature.

The "TEST" button is not intended as an "off" switch. Edit: except this one is designed for that purpose. Tripping the device when not in use might help the internal electronics avoid surge/spike damage. Might, depending on which side of the interrupt the electronics are on.

However, for an GFCI device kept in the mean outdoors, that is the least of your problems, as discussed elsewhere. The small amount of heat from the GFCI may help ward off condensation. The best way to extend the life of a GFCI is move it indoors.

Almost all GFCI devices, including "receptacles", are able to grant GFCI protection to additional devices. You can put one of those indoors somewhere earlier in the circuit, and have it grant GFCI protection to the rest of the circuit, including the outdoor receptacle. That becomes a plain receptacle with a "GFCI protected" sticker. Test using a 3-light tester which has a GFCI test button.