So first things first looking at designs I already had I came to the conclusion that its not practical to do what you want till your jumpships reach the 400 to 500 thousand ton range unless you sacrifice one of your docking collars for a combat dropship. So below is one of my 500 thousand ton jumpships modified to meet your requirements.
Sloop Modified Jumpship- Has 10 docking collars for great cargo hauling capacity. Mounts a single Laser AMS and ER Large Laser Per face to discourage attacks a bit. Has a four unit fighter wing and a two unit combat small craft wing. The double heat sinks double as spare parts for the small craft otherwise I would have used singles. The dropship has a size two infantry bay to repel boarders.
Sloop Class Jumpship
Mass: 500,000 tons
Technology Base: Inner Sphere (Advanced)
Introduced: 3065
Mass: 500,000
Battle Value: 1,413
Tech Rating/Availability: E/X-X-E-F
Cost: 1,839,172,917 C-bills
Fuel: 500 tons (1,250)
Safe Thrust: 0
Maximum Thrust: 0
Sail Integrity: 6
KF Drive Integrity: 10
Heat Sinks: 154 (308)
Structural Integrity: 1
Armor
Nose: 8
Fore Sides: 8/8
Aft Sides: 6/6
Aft: 4
Cargo
Bay 1: Fighter (4) 2 Doors
Bay 2: Cargo (1568.5 tons) 4 Doors
Bay 3: Small Craft (2) 1 Door
Bay 4: Infantry (Foot) (10) 1 Door
Ammunition:
None
Dropship Capacity: 10
Grav Decks: 1 (150 m)
Escape Pods: 0
Life Boats: 20
Crew: 6 officers, 25 enlisted/non-rated, 2 gunners, 74 bay personnel
Notes: Mounts 100 tons of standard aerospace armor.
Weapons: Capital Attack Values (Standard)
Arc (Heat) Heat SRV MRV LRV ERV Class
Nose (37 Heat)
2 ER PPC 30 2(20) 2(20) 2(20) 0(0) PPC
1 Laser AMS 7 0(3) 0(0) 0(0) 0(0) AMS
FRS/FLS (19 Heat)
1 Laser AMS 7 0(3) 0(0) 0(0) 0(0) AMS
1 ER Large Laser 12 1(8) 1(8) 1(8) 0(0) Laser
ARS/ALS (19 Heat)
1 Laser AMS 7 0(3) 0(0) 0(0) 0(0) AMS
1 ER Large Laser 12 1(8) 1(8) 1(8) 0(0) Laser
Aft (19 Heat)
1 Laser AMS 7 0(3) 0(0) 0(0) 0(0) AMS
1 ER Large Laser 12 1(8) 1(8) 1(8) 0(0) Laser
Light Small Craft Periphery- A temporary name this small craft is meant to be the answer to your requirement to be able to defeat an avenger. Has slightly better armor as well as the same speed. Due to being 1200 tons lighter compromises were necessary this craft uses 12 medium lasers requiring it to get in close but if it can do so it can take out the avenger without fail. Costs about a fifteenth of an avenger. Works in a two ship formation to box the avenger in to bring it into med laser range. Uses minimal advanced tech to make parts situation easier only Double heat sinks are advanced.
Light Small Craft Periphery
Type: Military Spheriod
Mass: 200 tons
Technology Base: Inner Sphere (Standard)
Introduced: 3065
Mass: 200
Battle Value: 3,140
Tech Rating/Availability: D/X-X-D-D
Cost: 16,287,650 C-bills
Fuel: 7.5 tons (600)
Safe Thrust: 7
Maximum Thrust: 11
Heat Sinks: 18 (36)
Structural Integrity: 14
Armor
Nose: 254
Sides: 214/214
Aft: 174
Cargo
Bay 1: Cargo (0.5 tons) 1 Door
Ammunition:
None
Escape Pods: 0
Life Boats: 0
Crew: 1 officer, 2 enlisted/non-rated, 2 gunners
Notes: Mounts 50 tons of standard aerospace armor.
Weapons
and Ammo Location Tonnage Heat SRV MRV LRV ERV
12 Medium Laser Nose 12.0 3 5 0 0 0
Budget Dagger Aero Fighter- A stripped down version of my Dagger Aero fighter lighter slightly slower and omitting targeting computer and ECM leaves me with a decent fighter costing only 2 mil. Price could be reduced further but the jumphip is expensive enough that there is a limit to pinching pennies. Uses minimal advanced tech to make parts situation easier only Double heat sinks are advanced.
Budget Dagger Aero Superiority Sloop
Mass: 40 tons
Frame: Unknown
Power Plant: 200 Fusion
Armor: Standard
Armament:
7 Medium Laser
Manufacturer: Unknown
Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 3060
Tech Rating/Availability: D/X-X-D-D
Cost: 2,065,360 C-bills
Type: Budget Dagger
Technology Base: Inner Sphere (Standard)
Tonnage: 40
Battle Value: 1,232
Equipment Mass
Engine 200 Fusion 8.5
Safe Thrust: 7
Max Thrust: 11
Structural Integrity: 8
Heat Sinks: 11 [22] 1
Fuel: 560 7.0
Cockpit 3
Armor Factor 216 13.5
Armor
Value
Nose 65
Wings 54/54
Aft 43
Weapons
and Ammo Location Tonnage Heat SRV MRV LRV ERV
5 Medium Laser NOS 5.0 3 5 0 0 0
Medium Laser RWG 1.0 3 5 0 0 0
Medium Laser LWG 1.0 3 5 0 0 0