Looking for ideas on the following well problem (brief summary below):

Background:

Horizontal frac well with multiple frac ports and frac balls in the horizontal after successfully fraccing the well.

Problem.

During milling out the 3rd ball and seat with CT the motor stalled and the CT is stuck in hole (yet to determine if it´s a mechanical lock-up or a build up of proppant/debris etc in the heel but indications were a mechanical lock up at the BHA after a motor stall).

Circulation was still possible after the stall (slight increase in pressure due to motor stall expected and seen) but no indications of a pack off further up the coil.

No returns of proppant or debris seen back at surface after numerous viscous pills pumped (with pumping pressures and rates as expected) indicating a mechanical lock up at the BHA when milling/milled through the frac port (cast iron) and motor stall rather than a bridge further up the well (although the jars not firing would indicate otherwise or else the jars have failed also).

Various attempts to fire the jars to free were unsuccessful (the jars not firing) and numerous attempts to free the string (pulling 80% of yield, working the string, pumping slick water, viscous pills, etc etc).

Eventually resorted to dropping a ball to activate the hydraulic disconnect in the CT BHA. The ball appears to have landed with a pressure increase (i.e. similar to a straight line and landing on volumes) but no disconnection seen (no decrease in applied pressure whatsoever indicating ball is on seat and not lodged in debris which would allow for some loss in pressure due to bypass). Pressured up to 100% over expected shear out value (6,000psi v 3,000psi shear out with three pins) without success and pulled the maximum allowable with applied pressure etc. Hydraulic disconnect such that we need to pull the inner mandrel out of the disconnect before circulation is established (i.e. the disconnect has potentially failed or we are stuck with proppant further up the hole and can´t pull out the 6 or so inches to allow circulation (although a pack off/stuck point due to proppant/debris further up the hole is contrary to returns seen previously (i.e. clean), pumping parameters etc)).

A lot of unknowns and the above is a brief overview but looking for ideas or any solutions to utilise in a stuck CT string with no circulation now possible other than : continue to work the string, bullhead down the backside and so on until the final option of e-line through the coil and cutting as deep as possible (also brings issues as we are not able to pump the cutter through the coil)?