You can definitely look into cheap or even free climbing/mantling component templates later on Fab or the Marketplace to just drop onto this character.
Since merging two separate Anim Blueprints (ABPs) is a nightmare, don't try to merge them. Here are two easy ways to fix the awkward pistol aiming transition and use those other TPS animations without a full ABP merge:
1. Fix the Awkward Pistol Aim Transition (The Blend Time Fix)
If the transition into or out of the pistol aim looks snappy, harsh, or awkward, you don't need to rebuild the logic. You just need to smooth out the transition timing.
Open my asset's Anim Blueprint (ABP) and go to the AnimGraph.
Look for the Blend Poses by Bool node or the state machine transition rule that toggles your IsAiming state.
Click on that blend node/transition line, look at the Details Panel, and find Blend Time.
Increase this value slightly (try changing it from 0.1 or 0.2 to 0.3 or 0.4). This instantly creates a much smoother, fluid interpolation between your normal idle/walk and your pistol aim pose! [1, 2]
2. Use the Other TPS Animations Without Merging ABPs (The Sub-ABP Method)
Instead of copy-pasting complex code between two massive ABPs, Unreal has a built-in feature designed exactly for this called a Sub-Anim Instance.
Open my asset's main ABP AnimGraph.
Right-click and add a Sub-Anim Instance node.
In its details panel, select your other TPS asset's Anim Blueprint.
This allows you to completely run that other project's movement states right inside my asset's graph, completely bypassing the need to manually.
Some youtube videos that might help your issues:
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